Furfurylthioacetone

ABSTRACT

The chemical compound furfurylthioacetone which is useful as a flavor additive for foodstuffs and beverages.

This is a division of application Ser. No. 482,693 filed June 24, 1974, now U.S. Pat. No. 3,900,581; which is a division of application Ser. No. 243,866 filed Apr. 13, 1972 and now abandoned which is a division of application Ser. No. 70,560 filed Sept. 8, 1970 now U.S. Pat. No. 3,702,253; which latter application is a continuation of now abandoned application Ser. No. 543,069 filed Apr. 18, 1966, which is a continuation-in-part of now abandoned application Ser. No. 452,342 filed Apr. 30, 1965.

The invention relates to flavor agents in general. More particularly the invention relates to chemical compounds or compositions which have been found to have utility in the alteration of flavor or flavor characteristics of substances, whether naturally occurring or synthetic. Still more particularly the invention relates to a group of chemical compounds which have been found to be useful in the area of flavor-note alteration, whether by the enchancement of flavors or flavor-notes that are characteristic in a substance, by the alteration of a flavor or a flavor-note from a less to a more desirable one, or by the complete or partial masking of a flavor or flavor-note.

As is generally recognized by those familiar with the art, the science of flavor technology is an extremely complex one. Although much is known about flavor and flavor technology there is still a great deal to be learned in the field and the body of scientific literature is being rapidly expanded by those working in the area. The technology of flavor synthesis and blending of various flavor elements to achieve certain desirable results is of great commercial importance at the present stage of industrial advance. Commercial production of consumer goods from synthetic starting materials is becoming more and more common, and desirable, as world population continues to increase its demands upon the finite capacity for the production of natural products. Industry is also continually seeking means of upgrading natural products -- methods of altering or enhancing the qualities of taste of less desirable natural products -- usually more abundant -- into more desirable product qualities. Often, for example, a product can be made commercially attractive only by masking or blanking out an undesirable flavor component. Formerly, before the advent of the flavor chemist and his technology, this unit of production would have been lost, or at least, would have had to have been re-processed to a useable quality. By the use of specifically designed flavoring agents, however, the undesirable flavor note can be eliminated or masked with another desirable one, and the expensive and time-consuming re-processing step eliminated or the production batch saved for use. Too, it is common in some segments of the industry, particularly the food industry, to add flavor agents to production units to enhance or bring out a desirable flavor characteristics of products -- and by so doing to render the product more desirable from a consumer preference standpoint.

It is the object of this invention therefore, to provide the flavor technologist with additional tools for his use in the alteration of food flavors, whether it be flavor or flavor-note alteration generally or the enhancement or improvement of flavor or flavor notes specifically.

It is a further object of the invention to furnish a group of chemical compositions which have utility in the technology of flavor alteration, whether added to solid or liquid compositions for human consumption, and which may be used in either solid or liquid form.

A further object of the invention is to describe several groups of chemical compounds having desirable utility as flavor agents which may be prepared synthetically, thus enabling the food technologist to alter or enhance his product without drawing upon a natural product for the flavor agent.

A still further object of the invention is to describe a group of chemical compounds capable of synthesis from readily available organic substances which may be used singly or in combination to alter the flavor or flavor notes of compositions for food use, whether used in micro-quantities such as parts-per-million or in larger quantities, as the dictates of the end results may require.

Other objects will become apparent to those skilled in the art as the description proceeds.

Thus, in accordance with the concept of the instant invention, there is set out below a series of groups of compounds which have been found to have utility as flavor agents and to represent valuable materials to the food technologist who wishes to alter the flavor components of foods or food products either liquid foods or beverages, such as fruit and vegetable juices, milk, coffee, tea, cocoa, chocolate, and the like or solid foods such as cereals, flours, confections, vegetables, meats, etc. The flavor agents may be used either in liquid or solid form and are used in quantities designed to give the desired results, as will be more clearly explained as the description proceeds.

The chemical compounds which have been found to have utility as flavor agents may be generally classified according to the following groups:

I -- diphenyls

Ii -- substituted Naphthalenes

Iii -- furan Hydrocarbons

Iv -- thiophene Hydrocarbons

V -- pyrrole Hydrocarbons

Vi -- pyridine Hydrocarbons

Vii -- pyrazine Hydrocarbons

Viii -- aliphatic and Aromatic Alcohols

Ix -- furan Ethers

X -- thiophene Ethers

Xi -- thiazole Alcohols

Xii -- pyridine Ethers and Alcohols

Xiii -- pyrazine Ethers and Alcohols

Xiv -- benzofuran Carbonyl Compounds

Xv -- thiophene Aldehydes

Xvi -- pyrrole Aldehydes

Xvii -- pyrazine Carbonyl Compounds

Xviii -- aliphatic and Aromaic Ketones

Xix -- furan Ketones

Xx -- thiophene Ketones

Xxi -- pyrrole Ketones

Xxii -- thiazole Carbonyl Compounds

Xxiii -- pyridine Carbonyl Compounds

Xxiv -- α-diketones

Xxv -- thiophene-α-diketones

Xxvi -- pyrrol-α-diketones

Xxvii -- furan Esters

Xxviii -- thiophene Esters

Xxix -- pyridine Esters

Xxx -- aromatic Sulfur Compounds

Xxxi -- furan Sulfur Compounds

Xxxii -- thiophene Sulfur Compounds

Xxxiii -- pyridine Sulfur Compounds

Xxxiv -- pyrrole Sulfur Compounds

Xxxv -- pyrazine Sulfur Compounds

Xxxvi -- phenols and Phenol Ethers

Xxxvii -- aliphatic Oxoalcohols

Xxxviii -- miscellaneous

The above groupings are selected more for reasons of chemical similarity than because of flavor alteration characteristics as will be more specifically described in relation to the more complete definition afforded each particular group.

The flavor agents or flavor modifying compositions of this invention are available to the food technologists in a variety of forms. It is usually preferable to use the agents in the form of a solution, for ease of dilution, exactitude of measurement, efficiency of distribution in the end use, etc. However the chemical nature of the compound, its solubility in acceptable solvents, its stability, and other characteristics may dictate the form in which it is used.

The amounts of the agents used is also subject to wide variation, of course. More concentrated materials, and those with the greatest degree of flavor modifying ability will be used in lesser amounts. Some degree of experimentation is, of course, required to achieve the desired results. A small, but flavor modifying amount, of the agents is blended with the material whose total flavor is to be altered, the amount depending upon the end result desired.

Two different types of methods were used in testing the compounds listed in this specification for their utility as flavor agents, flavor modifiers, flavor alteration agents, flavor-note enhancers, and the like. The first type method (A) served the purpose of determining the intrinsic taste, flavor and aroma of each individual compound. The second type methods (B) and (C) were used for testing the flavor- and aroma-modifying or -enhancing effects of the compounds hereinafter listed on coffee products and more particularly on spray-dried soluble coffee products commercially known as "instant coffee".

METHOD A

The vehicle used for testing the flavor compounds was a 65% solution of cane sugar in tap water. The flavor compounds were incorporated in this sugar syrup in the form of 1% or 1 per 1000 by weight solutions in 96% ethyl alcohol. The concentration of the flavor compounds in the sugar syrup varied between about 0.005 and 5 g. for 100 liters of syrup according to the varying strength of flavor compounds. Samples of each flavored sugar syrup were submitted to the members of the tasting panels. After tasting the samples each member had to give an evaluation of each flavor compound in terms of descriptive words.

In the evaluation of materials for the alteration or enhancement of coffee flavor or coffee flavor notes it is essential that the equipment used, coffee pots, cups, spoons, measuring equipment, etc. be absolutely clean prior to use.

METHOD B

The coffee base was prepared by dissolving 1 g. of a commercial spray-dried soluble coffee in boiling water. A sufficient number of pots was prepared to provide one pot for each flavor agent to be evaluated plus one control. The flavor agent was added to the coffee base in the form of a 1% or 1 per 1000 by weight alcoholic solution at concentrations varying between 0.005 and 5 g. of flavor agent for 100 liters of coffee base. The measured quantity of the flavor agent was added to a pot of the coffee base material, stirred well, and poured immediately into cups for the organoleptic evaluation. The taste tests were made within a short time (not more than 15 minutes) after the final composition to be tested was prepared.

The organoleptic evaluation involved grading a series of cups that were coded, the taster merely rating the coded cups against the standard or control which did not contain the flavor agent. The standard was placed at the first position in a series of cups. The tasters were asked to ascertain whether or not there existed differences in the flavor of the samples to be tested as compared with the control. The tasters were furthermore asked to describe and characterize the various flavor notes and types determined.

METHOD C

Using boiling Crystal Spring Water, to provide a clean starting taste, a 1.35% solution of relatively bland tasting commercially available spray-dried soluble coffee was prepared. The containers used -- preferably the lower portion of a glass coffee maker -- was absolutely clean, as was the other equipment used, e.g. cups and spoons.

A sufficient number of containers, or pots, were used to accommodate each flavor fraction to be studied, plus one control. The flavor fraction was measured carefully with a micro-syringe, adding from 2 to 150 microliters of the flavor fraction per pot. The mixture of coffee solution and flavor fraction was stirred and immediately poured into cups for tasting. At least 5 experienced tasters are used. The tasting should begin at least within 15 minutes after the solution is prepared. If not, the solution should be discarded and fresh solution prepared.

The cups are coded and the samples are not identified. A standard sample is included in which no flavor fraction has been added. The taster is asked to identify and describe the flavor enhancement or modification noted.

In the following specific description of the compounds of the Groups listed above (I- XXXVIII) there is first given the structural formula followed by a list of members of the grOUp which have been found to have outstanding utility in the concept of this invention. Immediately following the chemical name of each member there is given the commercial source or a literature reference giving a method for its preparation. Commercially available products will be identified by the abbreviation c.a., and may be obtained from FLUKA, A.G., Buchs S.G., Switzerland; ALDRICH CHEM. CO., Milwaukee, Wis; DR.F. RASCHIG GMBH, Ludwigshafen a. Rh., West-Germany; or K & K LABORATORIES INC., Plainview, NY. 11803.

In those instances wherein new compounds are described a detailed method of preparation is given following the list of the group members. New compounds will be identified by the abbreviation n.c.

The results of the organoleptic evaluation tests are set out in the group of TABLES following the detailed description of the groups of compounds

I -- Diphenyls

In this first group of compounds are included those having the structural formula: ##SPC1##

wherein R is hydrogen or an alkyl group, e.g. methyl.

Typical compounds are:1a. diphenyl c.a.b. 2-methyl-diphenyl c.a.c. 3-methyl-diphenyl c.a.d. 4-methyl-diphenyl c.a.e. 4,4'-dimethyl-diphenyl c.a.

Organoleptic evaluations as flavor agents are described in TABLE I below.

II -- Substituted Naphthalenes

Compounds in this group are those having the general formula:

The compounds enumerated above were evaluated organoleptically and gave the results set out in TABLE II below.

III -- FURAN HYDROCARBONS

The compounds of this group which have utility according to the inventive concept are selected from the class of compounds having the general formula: ##SPC2##

wherein R is hydrogen or an alkyl group containing from 1 to 3 carbon atoms;

compounds of the formula: ##SPC3##

wherein R is hydrogen or an alkyl or an alkenyl group of from 1 to 3 carbon atoms, provided that the sum of the carbon atoms of the substituent groups does not exceed 3; and

compounds of the formula: ##SPC4##

wherein R₁ is hydrogen or a methyl group and wherein R₂ is ##SPC5##

R₃ being hydrogen or a methyl group such that R₁ and R₃ are not both hydrogen.

Specific compounds included in this group of compounds are:

    1a.                                                                               2-vinyl-furan         Bull. 1947, 453                                       b. 2-(1)-pentenyl-furan  C.A. 1961, 85905f                                     2a.                                                                               benzofuran            c.a.                                                  b. 2-methyl-benzofuran   Soc. 1955, 3689                                       c. 2-ethyl-benzofuran    J.A.C.S. 73,754 (1951)                                d. 2,3-dimethyl-benzofuran                                                                              Soc. 1955, 3689                                       e. 2-vinyl-benzofuran    J.A.C.S. 73, 754 (1951)                               f. 2-isopropenyl-benzofuran                                                                             n.c.                                                  g. 7-methyl-benzofuran   J.Chem.Soc.1920, 1534                                 h. 7-ethyl-benzofuran    n.c.                                                  i. 2,7-dimethylbenzofuran                                                                               n.c.                                                  3a.                                                                               2,2'-difuryl          J.A.C.S. 73, 1271 (1951)                              b. 5-methyl-2,2'-difuryl-methane                                                                        C.A. 1957, 6594a                                      c. 5,5'-dimethyl-2,2'-difuryl-methane                                                                   Helv. 1932, 1068                                 

The new compounds included in Group III can be prepared by the methods described below.

2f. 2-Isopropenyl-benzofuran. According to the method described in J.A.C.S. 73, 754 (1951) 2-acetyl-benzofuran is reacted with methyl-magnesium bromide to form 2-(2-hydroxy-isopropyl)-benzofuran which is converted to its acetate. Pyrolysis of the acetate yields 2-isopropenyl-benzofuran of b.p. 81°-83°C./0.001 mm. Hg.

2h. 7-Ethyl-benzofuran is prepared by the method described in J.Chem.Sec. 1920, 1534, but using o-ethylphenol instead of o-cresol. The MS. of the product thus obtained shows the following ion peaks with the relative intensities given within brackets: 131 (100%), 146 (38%) and 77 (10%).

2i. 2,7-Dimethyl-benzofuran. 7-Methyl-benzofuran (of. compound (2) g.) is subjected to a WILSMEYER reaction to form 7-methyl-benzofuran-2-aldehyde which is converted into 2,7-dimethyl-benzofuran by a WOLFF-KISHNER reaction by the method described in Bull.Soc.Chim.France 29, 1875 (1952). The product thus obtained has the following peaks in its MS: 146 (100%), 145 (92%) and 131 (32%).

Organoleptic evaluations of this group of compounds are set out in TABLE III below.

IV -- THIOPHENE HYDROCARBONS

The thiophene hydrocarbons having utility in accordance with the instant invention concept are those compounds described by the structural formula: ##SPC6##

wherein R₁ and R₂ are hydrogen, methyl, ethyl, vinyl or propyl,

the compound of the formula: ##SPC7##

the compounds of the formula: ##SPC8##

wherein R₁ and R₂ are hydrogen or methyl groups, and wherein X is oxygen or sulfur;

the compounds of the formula ##SPC9##

wherein R₁ and R₂ are hydrogen or methyl groups, and

the compounds of the formula ##SPC10##

wherein R₁ and R₂ represent hydrogen or alkyl groups.

Typical compounds of this class of compounds are:1a. 2-methyl-thiophene c.a.b. 3-methyl-thiophene c.a.c. 2-ethyl-thiophene c.a.d. 3-ethyl-thiophene Bull. 1955, 424e. 2-propyl-thiophene J.A.C.S. 70, 391, Bull. 1955, 361f. 2-vinyl-thiopehen Bull.1955, 424g. 3-vinyl-thiophene Bull. 1955, 424h. 2-methyl-4-ethyl-thiophene J.A.C.S.75,989 (1953)i. 2-methyl-5-ethyl-thiophene J.A.C.S.75, 989 (1953)j. 2-methyl-5-propyl-thiophene J.A.C.S.75, 989 (1953)k. 2,5-dimethyl-thiophene c.a.2a. 2,3,3',2'-thiophenethiophene Soc. 1953, 18373a. 2,2'-dithienyl-methane J.A.C.S.73, 1270 (1951)b. 5,5'-dimethyl-2,2'-dithienyl-methane J.A.C.S.73, 1270 (1951)c. 2-furyl-2-thienyl-methane C.A. 57, 9776f(1962)d. (5-methyl-2-thienyl)-2-furyl-methane C.A. 57, 9776f (1962)4a. 2,2'-dithienyl J.A.C.S.78, 1958 (1956)b. 5,5'-dimethyl-2,2'-dithienyl-methane J.A.C.S.78, 1958 (1956)5a. benzothiophene c.a.b. 2-methyl-benzothiophene J.A.C.S.74, 664 (1952)

Organoleptic evaluations of these compounds are set out in TABLE IV below.

V -- PYRROLE HYDROCARBONS

Compounds of this group have the general formulae: ##SPC11##

wherein R is alkyl, e.g. ethyl, amyl, isoamyl, or alphamethyl-butyl, and ##SPC12##

wherein X is oxygen or sulfur and R is hydrogen or a methyl group, provided that, if X represents oxygen, R is methyl.

Typical compounds of this group include:1a. 1-ethyl-pyrrole Helv.10. 387 (1927)b. 1-n-amyl-pyrrole Helv.10, 387 (1927)c. 1-isoamyl-pyrrole Helv.10, 387 (1927)d. 1-(alphamethyl-butyl)-pyrrole Helv.10, 387 (1927)2a. 1-(5-methyl-2-furfuryl)-pyrrole n.o.i b.p.104°C./11 mm; prepared by the same method as (1) a.b. 1-thienyl-pyrrole J.Org.Chem.28,574 (1953)

Organoleptic test evaluations are set out in TABLE V below.

VI -- PYRIDINE HYDROCARBONS

The compounds of this group which have utility according to the instant concept are to be described as falling under the general formula: ##SPC13##

wherein R₁, R₂ and R₃ are hydrogen, alkyl, e.g. methyl, ethyl, isobutyl; alkenyl groups, e.g. vinyl, propenyl; aryl groups; or aralkyl groups; provided that the symbols R₁, R₂ and R₃ are not all hydrogen.1a. 2-methyl-pyridine c.a.b. 3-methyl-pyridine c.a.c. 3-ethyl-pyridine c.a.d. 2-allyl-pyridine Bull. 420, (1955)e. 4-isobutyl-pyridine Bull. 420, (1955)f. 2-(1)-propenyl-pyridine Ann. 247, 1 (1888)g. 4-(1)-propenyl-pyridine Ann. 247, 1 (1888)h. 2-methyl-5-ethyl-pyridine c.a.i. 2,3-dimethyl-pyridine c.a.j. 2,4-dimethyl-pyridine c.a.k. 2,5-dimethyl-pyridine c.a.l. 2,6-dimethyl-pyridine c.a.m. 3,4-dimethyl-pyridine c.a.n. 3,5-dimethyl-pyridine c.a.o. 2-vinyl-pyridine c.a.p. 4-methyl-pyridine c.a.q. 2-methyl-6-vinyl-pyridine c.a.r. 4-phenyl-pyridine c.a.s. 4-benzyl-pyridine c.a.t. 2-benzyl-pyridine c.a.u. 2-methyl-5-ethyl-pyridine c.a.

Organoleptic evaluations are set out in TABLE VI below.

VII -- PYRAZINE HYDROCARBONS

This important group of compounds have been found to have exceptional utility as flavor agents in accordance with the instant invention concept. Compounds of the group have the general formulae: ##SPC14##

wherein R₁ is hydrogen, alkyl, 1-pyrrolyl or 2-thienyl; and R₂ is alkyl or alkenyl, ##SPC15##

wherein R₁, R₂ and R₃ are alkyl groups having from 1 to 5 carbon atoms, ##SPC16##

wherein R₁, R₂ and R₃ are hydrogen or methyl groups, ##SPC17##

wherein R₁ and R₂ are alkyl groups containing from 1 to 3 carbon atoms, ##SPC18##

wherein R₁, R₂, R₃ and R₄ are alkyl groups containing from 1 to 6 carbon atoms, and ##SPC19##

wherein R₁ is methyl or ethyl and R₂ is alkyl or alkenyl with C₁ to C₆.

Compounds of this group which are of special interest include:

    1a.                                                                               2-methyl-3-ethyl-pyrazine                                                                            n.c.                                                  b. 2-methyl-3-isobutyl-pyrazine                                                                         n.c.                                                  c. 2-methyl-3-propyl-pyrazine                                                                           n.c.                                                  d. 2-methyl-3-isopropyl-pyrazine                                                                        n.c.                                                  e. 2-methyl-3-butyl-pyrazine                                                                            n.c.                                                  f. 2-methyl-3-amyl-pyrazine                                                                             n.c.                                                  g. 2-methyl-3-hexyl-pyrazine                                                                            n.c.                                                  h. 2,3-dimethyl-pyrazine Ber. 40, 4855 (1907)                                  i. 2,3-diethyl-pyrazine  n.c.                                                  j. 2-ethyl-3-vinyl-pyrazine                                                                             n.c.                                                  k. 2-methyl-3(5,6)-(pyrraolyl-1)-pyrazine                                                               n.c.                                                  l. 2-methyl-3-(thienyl-2)-pyrazine                                                                      n.c.                                                  m. 2-ethyl-pyrazine      J.Org.Chem.26, 3379                                                            (1961)                                                n. 2-propyl-pyrazine     J.Org.Chem.26, 3379                                                            (1961)                                                o. 2-isopropyl-pyrazine  J.Org.Chem.26, 3379                                                            (1961)                                                p. 2-vinyl-pyrazine      J.Org.Chem.26, 3379                                                            (1961)                                                q. 2-isopropenyl-pyrazine                                                                               n.c.                                                  r. 2-methyl-3-vinyl-pryazine                                                                            n.c.                                                  2a.                                                                               trimethyl-pyrazine    J.A.C.S. 72, 844(1950)                                b. 2,6-dimethyl-3-ethyl-pyrazine                                                                        n.c.                                                  c. 2,5-dimethyl-3-ethyl-pyrazine                                                                        n.c.                                                  d. 2,5-dimethyl-3-propyl-pyrazine                                                                       n.c.                                                  e. 2,6-diethyl-3-methyl-pyrazine                                                                        n.c.                                                  f. 2,5-diethyl-3-methyl-pyrazine                                                                        n.c.                                                  g. 2,5-dimethyl-3-butyl-pyrazine                                                                        n.c.                                                  h. 2,3-dimethyl-5-isoamyl-pyrazine                                                                      n.c.                                                  i. 2,5-dimethyl-3-isoamyl-pyrazine                                                                      n.c.                                                  j. 2,3-diethyl-5-methyl-pyrazine                                                                        n.c.                                                  3a.                                                                               5-methyl-quinoxaline  Ann.237, 336 (1887)                                   b. 2-methyl-quinoxaline  Org.Synth.30,86 (1950)                                c. 6-methyl-quinoxaline  Ann. 237, 336 (1887)                                  d. 2,3-dimethyl-quinoxaline                                                                             Ber. 40, 4852 (1907)                                  e. 2-methyl-3-ethyl-quinoxaline                                                                         Ber. 22, 526 (1889)                                   f. 2,3-diethyl-quinoxaline                                                                              J.A.C.S.79,1712 (1957)                                g. 2-methyl-3-propyl-quinoxaline                                                                        J.Chem.Soc. 1946, 54                                  h. 2-methyl-3-isopropyl-quinoxaline                                                                     J.Chem.Soc. 1953, 2822                                i. 2-methyl-3-butyl-quinoxaline                                                                         n.c.                                                  j. 2-methyl-3-isobutyl-quinoxaline                                                                      n.c.                                                  k. 2-methyl-3-amyl-quinoxaline                                                                          J.Chem.Soc. 1943, 322                                 l. 2-ethyl-quinoxaline   J.Chem.Soc. 1953, 2822                                4a.                                                                               2-methyl-6-ethyl-pyrazine                                                                            n.c.                                                  b. 2-methyl-6-propyl-pyrazine                                                                           J.Org.Chem. 27, 1355                                                           (1962)                                                c. 2,6-diethyl-pyrazine  n.c.                                                  d. 2-methyl-6-vinyl-pyrazine                                                                            n.c. -5a.     trimethyl-butyl-pyrazine n.c.           b. trimethyl-isoamyl-pyrazine                                                                           n.c.                                                  c. 2,5-dimethyl-3,6-dipropyl-pyrazine                                                                   n.c.                                                  d. 2,5-dimethyl-3,6-diisopropyl-pyrazine                                                                n.c.                                                  e. 2,5-dimethyl-3,6-dibutyl-pyrazine                                                                    n.c.                                                  f. 2,5-dimethyl-3,6-diisobutyl-pyrazine                                                                 n.c.                                                  g. 2,5-dimethyl-3,6-diamyl-pyrazine                                                                     n.c.                                                  h. 2,5-dimethyl-3,6-dihexyl-pyrazine                                                                    n.c.                                                  i. 2,3,5-trimethyl-6-hexyl-pyrazine                                                                     n.c.                                                  j. 2,5-dimethyl-3,6-diethyl-pyrazine                                                                    n.c.                                                  6a.                                                                               2-ethyl-5-methyl-pyrazine                                                                            n.c.                                                  b. 2-isopropyl-5-methyl-pyrazine                                                                        n.c.                                                  c. 2,5-diethyl-pyrazine  n.c.                                                  d. 2-methyl-5-vinyl-pyrazine                                                                            n.c.                                             

Organoleptic evaluations are set out in TABLE VII below.

The new compounds of this Group VII can be prepared as follows:

The 2,3-disubstituted pyrazines (formula (1)) can be obtained by a method comprising catalytically dehydrogenating with copper chromite the correspondingly substituted dihydropyrazines which, in turn, can be prepared by condensation of ethylene diamine with the corresponding alpha-diketones. By way of illustration the preparation of 2-methyl-3-ethyl-pyrazine is described in more details.

1a. 2-Methyl-3-ethyl-pyrazine. In a 3-necked flask equipped with a stirrer, means for cooling and a dropping funnel there was placed 150 g. of ethylene diamine in 500 ml. ether. After cooling to 0°C there was slowly added with stirring a solution of 250 g. of ethyl methyl diketone in 500 ml. of ether. After the addition was complete, the temperature was allowed to rise to room temperature and the mixture was heated on a water bath for a few minutes. The material separated into 2 phases and the water phase was discarded. The ether phase was dried with sodium sulfate, the solvent was removed by evaporation and the residue distilled under reduced pressure and an inert atmosphere. There was obtained 192 g. of the dihydropyrazine (62% yield), boiling point 61°-65°C./11 mm. Hg.

In an apparatus similar to that described by Bouveault in Bull IV, 3, 119 (1908) the dihydro pyrazine was distilled under reduced pressure under nitrogen atmosphere through a column containing copper chromite (Girdler G-13). The catalyst was heated to 300°C electrically and the effluent was passed through a Widmer column to separate the unhydrogenated material.

The product was condensed, dried and redistilled; a 90% yield was obtained of a product boiling at 57°C./10 mm. Hg.

The same method as used for compound (1) a. was applied for the preparation of the following compounds:

    1b.  2-methyl-3-isobutyl-pyrazine                                                                     b.p. 74°/10 mm. Hg.                              1c.  2-methyl-3-propyl-pyrazine                                                                       b.p. 71°-72°/10 mm. Hg.                   1d.  2-methyl-3-isopropyl-pyrazine                                                                    b.p. 59°/10 mm. Hg.                              1e.  2-methyl-3-butyl-pyrazine                                                                        b.p. 83°-84°/9 mm. Hg.                    1f.  2-methyl-3-amyl-pyrazine                                                                         b.p. 98°/10 mm. Hg.                              1g.  2-methyl-3-hexyl-pyrazine                                                                        b.p. 113°-115°/9 mm.Hg.                   1i.  2,3-diethyl-pyrazine                                                                             b.p. 69°-71°/12 mm. Hg.              

1j. 2-Ethyl-3-vinyl-pyrazine can be prepared from 2-ethyl-3-methyl-pyrazine by the method described in J.Org.Chem. 27, 1363 (1962). B.p. 75°-80°C./10 mm. Hg.

1k. 2-Methyl-3(5,6)-(pyrrolyl-1)-pyrazine can be prepared as follows: N-Pyrrolyl-lithium is prepared by reacting 0.242 mole (15.4 g.) of butyllithium (as 15% suspension in hexane) with 0.22 mole (14.7 g.) of pyrrole at -20°C. in the presence of 100 ml. of tetrahydrofuran. There is then added at room temperature a solution of 0.2 mole (25.6 g.) of 3(5,6)-chloro-2-methyl-pyrazine [obtained by the method described in J.Org.Chem. 26, 2356 (1961)] in 75 ml. of tetrahydrofuran. The reaction mixture is refluxed for 5 days and subjected to the usual treatments for purifying and isolating the reaction product which is then distilled. There is thus obtained 2-methyl-3(5,6)-N-pyrrolyl-pyrazine as a fraction distilling at 120°-124°C./10 Torr.

1l. 2-(Thienyl-2)-3-methyl-pyrazine is prepared as follows. A solution of 0.36 g. (0.006 mole) of ethylene diamine in 3 ml. of ether is cooled to 0°C. To this solution there is added slowly in a nitrogen atmosphere a solution of 0.94 g. (0.006 mole) of (thienyl-2) methyl diketone (obtained by oxidation of 2-propionyl-thiophene with selenium dioxide) in 3 ml. of absolute ether. The ether is gradually replaced by benzene, and water is removed as an azeotropic mixture with the latter solvent. The reaction product is fractionally distilled, and the fraction boiling at 85°-105°C./0.003 mm. Hg. is redistilled through a copper chromite column (GIRDLER G-13) heated at 350°C. There is thus obtained 2-(thienyl-2)-3-methyl-pyrazine of b.p. 94°C./0.03 mm. Hg.

1q. 2-Isopropenyl-pyrazine is obtained from 2-ethyl-pyrazine by the method described in J.Org.Chem. 27, 1363 (1962). It has the following peaks in the MS: 119 (100%), 120 (81%) and 67 (21%).

1r. 2-Methyl-3-vinyl-pyrazine is prepared from 2,3-diethyl-pyrazine by the same method as used for compound (1) q. It has a b.p. of 66°-67°C./13 mm. Hg.

2b. 2,6-Dimethyl-3-ethyl-pyrazine is prepared by the addition of an ethyl group at the 3-position of 2,6-dimethyl-pyrazine by the alkyl-lithium method described by Klein et al. in J.A.C.S. 73, 2949 (1951). The resulting product has a b.p. of 64°-66°C./8 mm. Hg.

2c. 2,5-Dimethyl-3-ethyl-pyrazine is prepared by the addition of an ethyl group at the 3-position of 2,5-dimethyl-pyrazine by the alkyl-lithium method described by Klein et al. (loc.cit.). The resulting product has a b.p. of 63°-68°C./8 mm. Hg.

2d. 2,5-Dimethyl-3-propyl-pyrazine is prepared by the addition of an n-propyl group at the 3-position of 2,5-dimethyl-pyrazine by the alkyl-lithium method described by Klein et al. (loc.cit.). The product is identified by mass spectrometry. It has a b.p. of 80°C./10 mm. Hg.

2e. 2,6-Diethyl-3-methyl-pyrazine is prepared by the introduction of a methyl group into the 3-position of 2,6-diethyl-pyrazine by the method of Klein et al. (loc.cit.). The product has a b.p. of 91°-92°C./13 mm. Hg.

2f. 2,5-Diethyl-3-methyl-pyrazine is prepared by the introduction of a methyl group into the 3-position of 2,5-diethyl-pyrazine by the method of Klein et al. (loc.cit.). The product was isolated by gas chromatography and was identified by mass spectrometry.

2g. 2,5-Dimethyl-3-butyl-pyrazine is prepared by introducing a butyl group into the 3-position of 2,5-dimethyl-pyrazine by the method of Klein et al. (loc.cit.). The resulting product has a b.p. of 91°C./9 mm. Hg.

2h. 2,3-Dimethyl-5-isoamyl-pyrazine is prepared by introducing an isoamyl group into the 5-position of 2,3-dimethyl-pyrazine by the method of Klein et al. (loc.cit.). The product is identified by mass spectrometry.

2i. 2,5-Dimethyl-3-isoamyl-pyrazine is prepared by introducing an isoamyl group into the 3-position of 2,5-dimethyl-pyrazine by the method of Klein et al. (loc.cit.). The product has a b.p. of 110°-120°C./13 mm. Hg.

2j. 2,3-Diethyl-5-methyl-pyrazine is prepared by the method described for the preparation of compound (1) a. in Group VII, using 1,2-diamino-propane instead of ethylene diamine and dipropionyl as the α-diketone. The product has a b.p. of 79°-80°C./12 mm. Hg.

3i. 2-Methyl-3-butyl-quinoxaline is obtained by the same method as compound (3d.) of Group VII. It has a b.p. of 153°C./9 mm. Hg.

3j. 2-Methyl-3-isobutyl-quinoxaline is obtained by the same method as compound (3e.) of Group VII. It has a m.p. of 94°-95°C.

4a. 2-Methyl-6-ethyl-pyrazine was obtained by the alkylation of 2,6-dimethyl-pyrazine by the method described by Levine and Behun in J.Org.Chem. 26, 3379 (1961). It has a boiling point of 54°-57°C./11 mm. Hg.

4c. 2,6-Diethyl-pyrazine was obtained by subjecting compound 4a. to a second alkylation by the procedure described above. It has a boiling point of 70° at 10 mm. Hg.

4d. 2-Methyl-6-vinyl-pyrazine is obtained by starting with 2,6-dimethyl-pyrazine and following the method of Levine et al. reported in J.Org.Chem. 27, 1363 (1962). It has a b.p. of 74°-75°/22 mm. Hg.

5a. 2,3,5-Trimethyl-6-butyl-pyrazine was prepared by introducing a butyl group into the 6-position of 2,3,5-trimethyl-pyrazine by the method of Klein et al. (loc.cit.). The product was isolated by gas chromatography and identified by mass spectrometry.

5b. 2,3,5-Trimethyl-6-isoamyl-pyrazine was prepared by introducing an isoamyl group into the 6-position of 2,3,5-trimethyl-pyrazine by the method of Klein et al. (loc.cit.). The product had a b.p. of 80°C./10 mm. Hg.

5c. 2,5-Dimethyl-3,6-dipropyl-pyrazine was prepared by first forming 3-oximino-2-hexanone by reacting 2-hexanone with nitrosyl chloride according to the method of BOUVEAULT, Bull. [3] 31, 1163 (1904). The autocondensation of two molecules of the imino-ketone in the presence of zinc and acetic acid [according to the method described in Chimia 11, 310 (1957)] yielded 2,5-dimethyl-3,6-dipropyl-pyrazine which had a b.p. of 109°-110°C./10 mm. Hg. 5d. 2,5-Dimethyl-3,6-diisopropyl-pyrazine was prepared by first forming 4-methyl-3-oximino-2-pentanone by reacting 4-methyl-2-pentanone with nitrosyl chloride according to the method of BOUVEAULT, Bull. [3] 31, 1163 (1904). The autocondensation of two moles of the imino-ketone in the presence of zinc and acetic acid [according to the method described in Chimia 11, 310 (1957)] yielded 2,5-Dimethyl-3,6-diisopropyl-pyrazine which had a b.p. of 91°C./8 mm. Hg.

5e. 2,5-Dimethyl-3,6-dibutyl-pyrazine was prepared by first forming 3-oxamino-2-heptanone by reacting 2-heptanone with nitrosyl chloride according to the method of BOUVEAULT, Bull. [3] 31, 1163 (1904). The autocondensation of two moles of the imino-ketone in the presence of zinc and acetic acid [according to the method described in Chimia 11, 310 (1957)] yielded 2,5-dimethyl-3,6-dibutyl-pyrazine which had a b.p. of 18°C./0.002 mm. Hg.

5f. 2,5-Dimethyl-3,6-diisobutyl-pyrazine was prepared by first forming 5-methyl-3-oximino-2-hexanone by reacting 5-methyl-2-hexanone with nitrosyl chloride according to the method of BOUVEAULT (loc.cit.). The autocondensation of two moles of the imino-ketone in the presence of zinc and acetic acid [according to the method described in Chimia 11, 310 (1957)] yielded 2,5-dimethyl-3,6-diisobutyl-pyrazine which had a b.p. of 69°-70°C./0.01 mm. Hg.

5g. 2,5-Dimethyl-3,6-diamyl-pyrazine was prepared by first forming 3-oximino-2-octanone by reacting 2-octanone with nitrosyl chloride according to the method of BOUVEAULT (loc.cit.). The autocondensation of two moles of the imino-ketone in the presence of zinc and acetic acid [according to the method described in Chimia 11, 310 (1957)] yielded 2,5-dimethyl-3,6-diamyl-pyrazine which had a b.p. of 78°C./0.03 mm. Hg.

5h. 2,5-Dimethyl-3,6-dihexyl-pyrazine was prepared by first forming 3-oximino-2-nonanone by reacting 2-nonanone with nitrocyl chloride according to the method of BOUVEAULT (loc.cit.). The autocondensation of two moles of the imino-ketone in the presence of zinc and acetic acid [according to the method described in Chimia 11, 310 (1957)] yielded 2,5-dimethyl-3,6-dihexyl-pyrazine which had a b.p. of 112°-120°C./0.01 mm. Hg.

5i. 2,3,5-Trimethyl-6-hexyl-pyrazine was prepared by introducing a hexyl group into the 6-position of 2,3,5-trimethyl-pyrazine by the method of Klein et al. (loc.cit.). The product had a b.p. of 89°-91°C./0.2 mm. Hg.

5j. 2,5-Dimethyl-3,6-diethyl-pyrazine is prepared by alkylation of 2,5-dimethyl-3-ethyl-pyrazine according to the alkyl-lithium method described by Klein et al. [J.A.C.S. 73, 2949 (1951)]. It has a b.p. of 83°-85°C./8 mm. Hg.

6a. 2-Ethyl-5-methyl-pyrazine was prepared by alkylation of 2,5-dimethyl-pyrazine following the procedure of Levine and Behun described in J.Org.Chem. 26, 3379 (1961). It has a boiling point of 60°C./11 mm. Hg.

6b. 2-Isopropyl-5-methyl-pyrazine was produced in the preparation of compound (6 ) a.) as a by-product and was separated from the reaction mixture by gas chromatography. Identification was confirmed by mass spectrometry.

6c. 2,5-Diethyl-pyrazine was obtained by subjecting compound (6a.) to a second alkylation by the procedure given for compound (6a.) above. It boils at 64°C. at 12 mm. Hg.

6d. 2-Methyl-5-vinyl-pyrazine was prepared by the method of Levine et al. described at J.Org.Chem. 27, 1363 (1962), starting from 2,5-dimethyl-pyrazine. It has a boiling point of 65°-66°C./12 mm. Hg.

VIII -- ALIPHATIC AND AROMATIC ALCOHOLS

This group comprises compounds having the general formula: ##EQU1## wherein 1. R₁ is hydrogen or an alkyl group, e.g. methyl, ethyl, propyl; and R₂ is an alkyl group having at least 4 carbon atoms, e.g. from 4 to 9 carbon atoms; or

2. R₁ is hydrogen or an alkyl group, e.g. comprising from 1 to 6 carbon atoms; and R₂ is an aryl group, e.g. phenyl; an aralkyl group, e.g., benzyl, phenylethyl; phenylpropyl; or an aralkenyl group, e.g. styryl, cinnamyl.

Compounds representative of this group include for instance:

    1a.  n-amylalcohol             c.a.                                            b.   isoamylalcohol            c.a.                                            c.   n-hexanol                 c.a.                                            d.   n-heptanol                c.a.                                            e.   n-octanol                 c.a.                                            f.   n-nonanol                 c.a.                                            g.   n-decanol                 c.a.                                            h.   2-heptanol                c.a.                                            i.   3-octanol                 c.a.                                            2a.  phenylethan-1-ol          c.a.                                            b.   phenylpropan-1-ol         c.a.                                            c.   cinnamyl alcohol          c.a.                                            d.   phenyl methyl carbinol    c.a.                                            e.   benzyl methyl carbinol    c.a.                                            f.   benzyl ethyl carbinol     c.a.                                            g.   benzyl butyl carbinol     n.c.                                            h.   benzyl amyl carbinol      n.c.                                            i.   benzyl isoamyl carbinol   n.c.                                            j.   benzyl hexyl carbinol     n.c.                                       

The new compounds of this Group VIII can be prepared as follows:

2g. Benzyl butyl carbinol. To a solution of 1.05 mole of butyl-magnesium bromide in 400 ml. of ether there is added a solution of 1 mole (120 g.) of phenylacetaldehyde in 300 ml. of ether at -8° to -12°C. within 3 to 4 hours. The reaction mixture is heated to about 20°C. and worked up by conventional methods. Distillation of the crude reaction product yields 99 g. of benzyl butyl carbinol of b.p. 88°-91°C./0.06 Torr; d₄ ²⁰ = 0.9485; n_(D) ²⁰ = 1.5059.

The same method is used for preparing:

2h. Benzyl amyl carbinol, b.p. 81°C./0.01 Torr.

2i. Benzyl isoamyl carbinol, b.p. 142°-143°C./13 Torr; d₄ ²⁰ = 0.9377; n_(D) ²⁰ = 1.5009.

2j. Benzyl hexyl carbinol, b.p. 95°C./0.01 Torr; d₄ ²⁰ = 0.9339; n_(D) ²⁰ = 1.4997.

Organoleptic evaluation data are listed in TABLE VIII below.

IX -- FURAN ETHERS

The compounds of this group have the general formula: ##SPC20##

wherein R₁ and R₂ are hydrogen; alkyl, e.g. methyl, ethyl; aryl, e.g. phenyl, alkylphenyl; furfuryl, or alkylfurfuryl groups.

Compounds representative of this group include the following:

    1a.  furfuryl methyl ether                                                                             Ber. 56, 1004 (1923)                                   b.   furfuryl ethyl ether                                                                              Ber. 56, 1004 (1923)                                   c.   furfuryl phenyl ether                                                                             Bull. 1938, 1151                                       d.   5-methyl-furfuryl furfuryl ether                                                                  n.c.                                                   e.   difurfuryl ether   Am.Soc. 49, 1066 (1927)                           

1d. 5-Methyl-furfuryl furfuryl ether was prepared by the procedure described by J. E. Zanetti in J.Am.Chem.Soc. 49, 1066 (1927) for the difurfuryl ether, starting with 5-methyl-furfuryl bromide (Compt.Rend. 222, 1441 (1946)) instead of furfuryl bromide of Zanetti. The product was isolated by ether extraction of the crude mixture after having diluted with water. For purification the ether extract was distilled twice -- b.p. 68°-70°C. at 0.01 mm./Hg vacuum. The product was a viscous colourless liquid, darkening rapidly on contact with air.

Organoleptic evaluations are tabulated in TABLE IX.

X -- THIOPHENE ETHERS

This group of compounds are described by the structural formula: ##SPC21##

wherein R is an alkyl group, phenyl, alkylphenyl, furfuryl, alkylfurfuryl, or thenyl group, and includes for example:

    1a.  thenyl methyl ether                                                                             J.A.C.S. 49, 1066 (1927)                                                       J.A.C.S. 50, 1960 (1928)                                 b.   dithenyl ether   n.c.                                                     c.   furfuryl thenyl ether                                                                           n.c.                                                

The new compounds of this group were prepared as follows:

1b. Diethyl ether. To a suspension of 1.32 g. (0.01 mole) of cloromethylthiophene [obtained by the method of F. F. BLICKE, J.A.C.S. 64, 477 (1942)] and 1.2 g. (0.02 mole) of powdered potassium hydroxide in 10 ml. of ether there is added a solution of 3.5 g. (0.03 mole) of thenyl alcohol in 10 ml. of ether. The reaction mixture is stirred for 1 hour at room temperature, then refluxed for 30 minutes and finally allowed to stand over night. After filtration the ethereal solution is concentrated and the residue fractionally distilled. There is obtained 0.22 g. (10%) of dithenyl ether having a b.p. of 99°C./0.01 mm. Hg. and a m.p. of 36.5°. 1c. Furfuryl thenyl ether is obtained by the same method as used for preparing compound (1) b., but using furfuryl alcohol instead of thenyl alcohol. The product thus obtained had a b.p. of 50°C./0.01 mm. Hg.

Organoleptic evaluation data on representatives of this group of compounds are set out in TABLE X below.

XI -- THIAZOLE ALCOHOLS

Compounds of this group have the following structural formula: ##SPC22##

wherein R is an alkyl group, e.g. containing from 1 to 4 carbon atoms, or an alkenyl group, e.g. vinyl.

Representative compounds include the following:

    1a.  methyl (4-methyl-thiazolyl-2) carbinol                                                                   n.c.                                            b.   ethyl (4-methyl-thiazolyl-2) carbinol                                                                    n.c.                                            c.   vinyl (4-methyl-thiazolyl-2) carbinol                                                                    n.c.                                            d.   isobutyl (4-methyl-thiazolyl-2) carbinol                                                                 n.c.                                       

The new compounds of this Group X can be prepared as follows:

1a. Methyl (4-methyl-thiazolyl-2) carbinol was prepared by starting from 4-methyl-thiazole and substituting the hydrogen atom in the 2-position by lithium by reaction with butyl-lithium. The resulting metal-organic compound was reacted with acetaldehyde [cf. J.A.C.S. 74, 6260 (1952)]. The resulting product has a b.p. of 102 -103°C./9 mm. Hg.

1b. Ethyl (4-methyl-thiazolyl-2) carbinol was prepared by starting from 4-methyl-thiazole and substituting the hydrogen atom in the 2-position by lithium by reaction with butyl-lithium. The resulting metal-organic compound was reacted with propionaldehyde [cf. J.A.C.S. 74, 6260 (1952)]. The resulting product had a b.p. of 110°-115°C./9 mm. Hg. and a m.p. of 67°-72°C.

1c. Vinyl (4-methyl-thiazolyl-2) carbinol was prepared by starting from 4-methyl-thiazole and substituting the hydrogen atom in the 2-position by lithium by reaction with butyl-lithium. The resulting metal-organic compound was reacted with acrolefin [cf. J.A.C.S. 74, 6260 (1952)]. The resulting product had a b.p. of 66°C./0.005 mm.Hg.

1d. Isobutyl (4-methyl-2-thiazolyl) carbinol was prepared by starting from 4-methyl-thiazole and substituting the hydrogen atom in the 2-position by lithium by reaction with butyl-lithium. The resulting metal-organic compound was reacted with isovaleraldehyde [cf. J.A.C.S. 74, 6260 (1952)]. The resulting product had a b.p. of 94°C./0.1 mm. Hg.

Organoleptic evaluations are set out in TABLE XI below.

XXI -- PYRIDINE ETHERS AND ALCOHOLS

Compounds of this group are found to have the following general formula: ##SPC23##

wherein R₁ is hydrogen or an alkoxy group, R₂ is hydrogen or an alkyl group, and n is 0, 1 or 2.

Examples of this group include:

    1a.  2-methoxy-pyridine        c.a.                                            b.   2-butoxy-pyridine         n.c.                                            c.   2-methoxymethyl-pyridine  c.a.                                            d.   2-methoxymethyl-6-methyl-pyridine                                                                        c.a.                                            e.   2-hydroxymethyl-pyridine  c.a.                                            f.   3-hydroxymethyl-pyridine  c.a.                                            g.   4-hydroxymethyl-pyridine  c.a.                                            h.   2-hydroxymethyl-6-methyl-pyridine                                                                        c.a.                                            i.   2-(2-hydroxyethyl)-pyridine                                                                              c.a.                                            j.   2-(2-ethoxyethyl)-pyridine                                                                               c.a.                                       

1b. 2-Butoxy-pyridine was prepared according to the method described in J.A.C.S. 69, 1803 (1947) by condensing 0.17 mole of 2-bromo-pyridine with 0.195 mole of sodium butoxide. By distillation of the reaction product there were obtained 15 g. of 2-butoxy-pyridine distilling at 78°C./10 mm.Hg. n_(D) ²³ = 1.4880; d₄ ²³,4 = 0.9723.

Organoleptic evaluations are set out in TABLE XII below.

XIII -- PYRAZINE ETHERS AND ALCOHOLS

Compounds of this group are represented by the general formula: ##SPC24##

wherein R represents hydrogen or an alkyl group and n is 0, 1 or 2.

Examples of compounds covered by this formula are:

    1a.  2-hydroxymethyl-pyrazine                                                                        J.Org.Chem. 28, 1898 (1963)                              b.   2-methoxymethyl-pyrazine                                                                        n.c.                                                     c.   2-ethoxymethyl-pyrazine                                                                         n.c.                                                

Compounds (1b.) and (1c.) were prepared by reacting 2-chloromethyl-pyrazine with the corresponding sodium alkoxide according to the same method as used for the preparation of sulfides [cf. HOUBEN-WEYL, 4th edition, vol. 9, 97 (1955)]. The products thus obtained had the following boiling points:

compound (1b.): 51°C./8 mm. Hg.;

compound (1c.): 75°C./8 mm. Hg.

Organoleptic evaluations are set out in TABLE XIII below.

XIV -- BENZOFURAN CARBONYL COMPOUNDS

This group of compounds has the following general formula: ##SPC25##

wherein R₁ and R₂ may be hydrogen or alkyl.

Examples of compounds included in this definition are:

    1a.  benzofuran-2-aldehyde                                                                              Bull. 1962, 1875                                      b.   2-acetyl-benzofuran J.A.C.S.73, 754 (1951)                                c.   7-methyl-benzofuran-2-aldehyde                                                                     n.c.                                             

1c. 7-Methyl-benzofuran-2-aldehyde was prepared by formylating 7-methyl-benzofuran according to the same method as used for the preparation of benzofuran-2-aldehyde. The product thus obtained has the following ion peaks in its mass spectrum: 160 (100%), 159 (62%) and 131 (33%).

Organoleptic evaluations are set out in TABLE XIV below.

XV -- THIOPHENE ALDEHYDES

Compounds of this group have the general formulae: ##SPC26##

wherein R is hydrogen, or an alkyl or thenyl group; amd ##SPC27##

wherein R₁ and R₂ represent hydrogen or alkyl.

compounds in this group include for instance:

    1a.                                                                               Thiophene-2-aldehyde                                                                            c.a.                                                       b. 5-methyl-thiophene-2-aldehyde                                                                   Org.Syn. 36, 74 (1956)                                     c. 3-methyl-thiophene-2-aldehyde                                                                   *b.p. 88-89°C./10 mm. Hg.                           d. 5-propyl-thiophene-2-aldehyde                                                                   *b.p. 64-65°C./0.002 mm. Hg.                        e. 5-thenyl-thiophene-2-aldehyde                                                                   *m.p. 31-32°C.                                      *prepared according to the same method as used for compound 1b.                2a.                                                                               benzothiophene-2-aldehyde                                                                       J.A.C.S.74, 2935 (1952)                                    b. 2-acetyl-benzothiophene                                                                         Compt.Rend.234, 736 (1951)                            

Organoleptic evaluations are set out in TABLE XV below.

XVI -- PYRROLE ALDEHYDES

Compounds of this group have the structural formula ##SPC28##

wherein R is an alkyl, furfuryl or thenyl group.

Representative compounds include, for example:1a. 1-ethyl-pyrrole-2-aldehyde n.c.b. 1 butyl-pyrrole-2-aldehyde Helv. 13, 349 (1930)c. 1-butyl-pyrrole-3-aldehyde n.c.d. 1-amyl-pyrrole-2-aldehyde n.c.e. 1-amyl-pyrrole-3-aldehyde n.c.f. 1-α-methylbutyl-pyrrole-2-aldehyde n.c.g. 1-α-methylbutyl-pyrrole-3-aldehyde n.c.h. 1-furfuryl-pyrrole-2-aldehyde Helv. 13, 349 (1930)i. 1-furfuryl-pyrrole-3-aldehyde n.c.j. 1-thenyl-pyrrole-2-aldehyde n.c.k. 1-isoamyl-pyrrole-2-aldehyde Helv. 13, 349 (1930)

The new compounds of this group XVI can be prepared as follows:

1a. 1-Ethyl-pyrrole-2-aldehyde was prepared from 1-ethyl-pyrrole [obtained by the method described in Helv. 10, 387 (1927)] by introducing a formaldehye group following the technique described in Org.Synth. 36, 74 (1956). The product boiled at 73°-75°C./7mm. Hg.

1c. 1-Butyl-pyrrole-3-aldehyde was prepared by the same method as used for compound (1) a. It has a b.p. of 148°-150°C./11 mm. Hg.

1d. 1-Amyl-pyrrole-2-aldehyde was prepared by the same method as used for compound (1) a. It has a b.p. of 111°-112°C./11 mm. Hg.

1e. 1-Amyl-pyrrole-3-aldehyde was prepared by the same method as used for compound (1) a. It has a b.p. of 155°-160°C./11 mm.Hg.

1f. 1-α-Methylbutyl-pyrrole-2-aldehyde was prepared by the same method as used for compound (1) a. It has a b.p. of 103°-105°C./11 mm. Hg.

1g. 1-α-Methylbutyl-pyrrole-3-aldehyde was prepared by the same method as used for compound (1) a. It has a b.p. of 150°C./11 mm. Hg.

1h. 1-Furfuryl-pyrrole-2-aldehyde was prepared starting with 1-furfuryl-pyrrole described by Reichstein in Helv. 15, 1450 (1932) as well as Gianturco et al. in Tetrahedron 20, 1763 (1964). The aldehyde group was introduced by the Vilsmeyer reaction (e.g. by the method described in Bull. 1962, 1989). A small amount of the corresponding 3-aldehyde is obtained as a by-product and can be separated by fractional distillation. The 2-aldehyde boils at 139°-140°C./12 mm. Hg. and is a viscous colorless oil. The 3-aldehyde has a b.p. of 190°C./12 mm. Hg.

1j. 1-Thenyl-pyrrole-2-aldehyde was prepared by the same method as used for compond (1) h. It has a b.p. of 98°C./0.005 mm. Hg.

The organoleptic evaluations are shown in TABLE XVI below.

XVII -- PYRAZINE CARBONYL COMPOUNDS

Compounds of this group have the general formula: ##SPC29##

wherein R is hydrogen or an alkyl group and n is 0 or 1.

Examples of this group include:1a. 2-formyl-pyrazine C.A. 58. 10180b (1963)b. 2-acetyl-pyrazine J.A.C.S. 74, 3621 (1952)c. 2-acetonyl-pyrazine J.Org.Chem.23, 406 (1953)

Organoleptic evaluations are tabulated in TABLE XVII below.

XVIII -- ALIPHATIC AND AROMATIC KETONES

The compounds of this group are defined by the following general formula:

    R.sub.1 --CO--R.sub.2                                      (1)

wherein R₁ is an alkyl group having 1 to 3 carbon atoms and R₂ is an alkyl group having from 3 to 11 carbon atoms, or a phenyl or benzyl group.

Examples of compounds corresponding to this definition are as follows:

    1a.  methyl amyl ketone                                                                              c.a.                                                     b.   methyl hexyl ketone                                                                             c.a.                                                     c.   methyl heptyl ketone                                                                            c.a.                                                     d.   methyl cetyl ketone                                                                             c.a.                                                     e.   methyl nonyl ketone                                                                             c.a.                                                     f.   methyl decyl ketone                                                                             c.a.                                                     g.   methyl undecyl ketone                                                                           c.a.                                                     h.   ethyl butyl ketone                                                                              c.a.                                                     i.   ethyl amyl ketone                                                                               c.a.                                                     j.   dipropyl ketone  c.a.                                                     k.   propyl isopropyl ketone                                                                         J.A.C.S. 63, 3163 (1941)                                 l.   di-isopropyl ketone                                                                             J.A.C.S. 59, 1826 (1937)                                 m.   acetophenone     c.a.                                                     n.   propiophenone    c.a.                                                     o.   isopropyl phenyl ketone                                                                         c.a.                                                     p.   methyl benzyl ketone                                                                            c.a.                                                     q.   ethyl benzyl ketone                                                                             c.a.                                                

Organoleptic evaluations are tabulatd in TABLE XVIII below.

XIX -- FURAN KETONES

This family of compounds have the following general formula: ##SPC30##

wherein n is 0, 1 or 2 and wherein R₁ is hydrogen or methyl, and R₂ is alkyl.

Representative examples of compounds in this group include:

    1a.                                                                               2-acetyl-furan     c.a.                                                     b. 2-propionyl-furan  J.A.C.S. 72, 3695 (1950)                                 c. 2-butyryl-furan    J.A.C.S. 72, 3695 (1950)                                 d. 2-valeryl-furan    J.A.C.S. 72, 3695 (1950)                                 e. 5-methyl-2-acetyl-furan                                                                           J.A.C.S. 72, 3695 (1950)                                 f. 5-methyl-2-propionyl-furan                                                                        J.A.C.S. 72, 3695 (1950)                                 g. furfuryl methyl ketone                                                                            Ber. 76, 192 (1943)                                      h. furfuryl ethyl ketone                                                                             J.Org.Chem. 15, 8 (1950)                                 i. (5-methyl-furfuryl) methyl ketone                                                                 n.c.                                                     j. (5-methyl-furfuryl) ethyl ketone                                                                  n.c.                                                     k. 4-furyl-2-butanone J.A.C.S. 72, 3695 (1950)                                 l. 4-(5-methylfuryl)-2-butanone                                                                      Ber. 76, 192 (1943)                                      m. 1-(5-methylfuryl)-3-pentanone                                                                     n.c.                                                

The new compounds of this group can be prepared as follows:

1i. (5-Methyl-furfuryl) methyl ketone was prepared according to the procedure described by Hass et al. in J.Org.Chem. 15, 8 (1950) by condensing 5-methyl-furfuryl-aldehyde with nitroethane. The product has a b.p. of 75°c./10 mm. Hg.

1j. (5-Methyl-furfuryl) ethyl ketone was prepared by the same method as used for compound (1) i., except that 1-nitropropane was used instead of nitroethane. The product has a b.p. of 97°-100°C./15 mm. Hg.

1m. 1-(5-Methylfurfuryl-3-pentanone was prepared by the method described in Ber. 76, 192 (1943). It has a b.p. of 101°-102°C./11 mm. Hg.

Organoleptic evaluation data are set out in TABLE XIX below.

XX -- THIOPHENE KETONES

Compounds of this group which have been found to have utility in the concept of the instant invention have the following general formulae: ##SPC31##

wherein n is 0 or 1, R₁ is hydrogen or alkyl and R₂ is alkyl; and ##SPC32##

wherein n is 0 or 1.

Representative compounds include:1a. 2-acetyl-thiophene J.A.C.S. 72, 3695 (1950)b. 3-methyl-2-acetyl-thiophene J.A.C.S. 72, 3695 (1950)c. 4-methyl-2-acetyl-thiophene J.A.C.S. 72, 3695 (1950)d. 3-methyl-2-propionyl-thiophene J.A.C.S. 72, 3695 (1950)e. 5-methyl-2-propionyl-thiophene J.A.C.S. 72, 3695 (1950)f. 2-butyryl-thiophene J.A.C.S. 72, 3695 (1950)g. 5-methyl-2-acetyl-thiophene J.A.C.S. 72, 3695 (1950)h. 2-propionyl-thiophene J.A.C.S. 72, 3695 (1950)i. 2-acetylmethyl-thiophene C.A. 51, 10509c (1957)2a. 5,5'-diacetyl-dithienyl-2,2'-methane J.A.C.S. 73, 1270 (1951)b. 5,5'-diacetyl-dithienyl-2,2' J.A.C.S. 28, 1958 (1956)

Organoleptic evaluation data are set out in TABLE XX below.

XXI -- PYRROLE KETONES

Compounds of this group have the general formulae: ##SPC33##

wherein X is oxygen or sulfur, R₁ is an alkyl group, and R₂ is hydrogen or an alkyl group; ##SPC34##

wherein R is an alkyl group; ##SPC35##

wherein R₁ is hydrogen or an alkyl group and R₂ is an alkyl group; ##SPC36##

wherein R₁, R₂ and R₄ represent hydrogen or alkyl groups and R₃ is an alkyl group.

Compounds which are representative of this group include:1a. 1-furfuryl-2-acetyl-pyrrole n.c.b. 1-thenyl-2-acetyl-pyrrole J.A.C.S. 85, 2859 (1963)c. 1-thenyl-3-acetyl-pyrrole J.A.C.S.85, 2859 (1963)2a. 1-acetyl-pyrrole Chem.& Ind. 1965, 1426b. 1-propionyl-pyrrole Ber. 89, 1938 (1956)3a. 2-methyl-5-acetyl-pyrrole c.a.b. 1,2-dimethyl-5-acetyl-pyrrole n.c.4a. 2,5-dimethyl-3-acetyl-pyrrole Beilstein XXI, 277 (1935)b. 1-methyl-3-acetyl-pyrrole n.c.

The new compounds included in this group can be prepared as follows:

1a. 1-Furfuryl-2-acetyl-pyrrole was prepared starting from 1-furfuryl-pyrrole described by Reichstein in Helv. 15, 1450 (1932) as well as Gianturco et al. in Tetrahedron 20, 1763 (1964). Acetylation by reaction of the Grignard intermediate with acetyl chloride [cf. Chem. Ber. 47, 1416 (1914)] led to the desired ketone. (A small amount of the 3-isomer was also obtained, separable by fractional distillation). The product boils at 100°-102°C./0.03 mm Hg. and crystallizes on standing. Recrystallization from a mixture of methylene dichloride and petroleum ether gave a white crystalline product with a m.p. of 42°-43°C.

3b. 1,2-Dimethyl-5-acetyl-pyrrole was obtained by acetylating 1,2-dimethylpyrrole according to the method described in Ber. 47, 1416 (1914) [cf. also J.A.C.S. 85, 2859 (1963)]. The product has a b.p. of 102°-106°C./10 mm. Hg.

4b. 1-Methyl-3-acetyl-pyrrole was obtained as a by-product in the synthesis of 1-methyl-2-acetyl-pyrrole according to the method described in Ber. 47, 1416 (1914). The product has a b.p. of 130°-132°C./12 mm. Hg.

Evaluation data are set out in TABLE XXI below.

XXII ' THIAZOLE CARBONYL COMPOUNDS

Compounds of this group have the following general formula: ##SPC37##

wherein R₁ and R₂ are hydrogen or alkyl groups.

Representative compounds of this group are:1a. 4-methyl-2-acetyl-thiazole Bull. 20, 702 (1953)b. 4-methyl-2-propionyl-thiazole n.c.c. 5-methyl-2-acetyl-thiazole Bull. 20, 702 (1953)d. 4-methyl-2-butyryl-thiazole n.c.e. 4-methyl-2-formyl-thiazole n.c.

The new compounds included in this group can be prepared as follows:

1b. 4-Methyl-2-propionyl-thiazole was prepared according to the method described in Bull. 20, 702 (1953) by reacting 4-methyl-thiazole with ethyl-magnesium bromide and acylating the obtained Grignard intermediate with propionyl chloride. The product has a b.p. of 83°-88°C./9 mm. Hg.

1d. 4-Methyl-2-butyryl-thiazole was prepared by the same method as compound (1) b, but using butyric anhydride as the acylating agent. The product has a b.p. of 110°-115°C./8 mm. Hg.

1e. 4-Methyl-2-formyl-thiazole was prepared by oxidizing 2-hydroxymethyl-4-methyl-thiazole with chromic acid in a sulfuric acid medium according to the method described in J.A.C.S. 53, 1470 (1931). The product was identified by mass spectrometry (peaks M/e and relative intensity): 71 (100%), 127 (97%) and 72 (48%).

Organoleptic evaluation data are set out in TABLE XXII below.

XXIII -- PYRIDINE CARBONYL COMPOUNDS

Compounds of this group have the general formula: ##SPC38##

wherein R₁ represents hydrogen, an alkyl group or a phenyl group, R₂ represents hydrogen, an alkyl group or an acyl group and n is 0, 1 or 2.

Representative compounds include:

    1a.  2-acetyl-pyridine         c.a.                                            b.   6-methyl-2-acetyl-pyridine                                                                               c.a.                                            c.   3-acetyl-pyridine         c.a.                                            d.   4-acetyl-pyridine         c.a.                                            e.   pyridine-2-aldehyde       c.a.                                            f.   pyridine-3-aldehyde       c.a.                                            g.   pyridine-4-aldehyde       c.a.                                            h.   6-methyl-pyridine-2-aldehyde                                                                             c.a.                                            i.   2-benzoyl-pyridine        c.a.                                            j.   3-benzoyl-pyridine        c.a.                                            k.   4-benzoyl-pyridine        c.a.                                            l.   2,6-diacetyl-pyridine     c.a.                                            m.   4-(γ-pyridyl)-butan-2-one                                                                          n.c.                                       

The new compound, 4-(γ-pyridyl)-butan-2-one, was prepared as follows:

8 ml. of 2-n NaOH solution were added to a mixture of 10.8 g. (0.1 mole) of pyridine-4-aldehyde, 100 ml. of water and 10 ml. of acetone at 12°-15°C. After a reaction time of 3 minutes the reaction mixture waS neutralized with 10 % aqueous acetic acid, saturated with NaCl and extracted with ether. After removal of the ether the residue was distilled. There were obtained 8.4 g. of 4-(γ-pyridyl)-3-buten-2-one as a yellow oil of b.p. 135°-138°C./0.07 Torr. 5.24 g. of this product were dissolved in 30 ml. of ethanol and hydrogenated in the presence of 4 g. of Ni-catalyst. Distillation of the reaction product yielded 4-(γ-pyridyl)-butan-2-one of b.p. 83°-85°C./0.05 Torr; n₄ ²⁷ = 1.047; n_(D) ²⁷ = 1.516.

Organoleptic evaluation data are set out in TABLE XXIII below.

XXIV -- ALPHA-DIKETONES

Compounds of this group which have been found to have utility in the concept of this invention are of the formulae:

    CH.sub.3 COCOR                                             (1)

    c.sub.2 h.sub.5 cocor                                      (2)

wherein R is an alkyl group or a phenyl group.

Compounds representative of this group include:

    1a.                                                                               acetylbutyryl  J.Chem.Soc. 1946, 56                                         b. acetylisobutyryl                                                                              Ber. 22, 2121 (1889)                                         c. acetylisovalerianyl                                                                           Ber. 22, 2122 (1889)                                         d. acetyloaproyl  J.pr.Ch.[2] 58, 402 (1898)                                                     n.sub.D.sup.20 - 1.4214; d.sub.4.sup.20 - 0.9183             e. acetylbenzoyl  c.a. (British Drug House)                                    f. 5-methyl-heptanedione-2,3                                                                     n.c.                                                         g. 5-methyl-octanedione-2,3                                                                      n.c.                                                         h. acetylvalerianyl                                                                              n.c.                                                         i. acetylheptanoyl                                                                               n.c.                                                         2a.                                                                               dipropionyl    Bull.[3], 31, 629,650 (1906)                                 b. heptane-3,4-dione                                                                             Bull.[3], 31, 1174 (1904)                                    c. 5-methyl-heptane-3,4-dione                                                                    n.c.; prepared by the                                                          method in Bull.[3], 31, 1145                                                   (1904); b.p. 55°C./12 mm.Hg.                     

The new compounds included in this group can be obtained as follows:

1f. 5-Methyl-heptan-2,3-dione. 0.33 Mole of acetol, 0.33 mole of α-methylbutanal and 2.5 ml. of conc. HCl were heated in a flask equipped with a Raschig column (length 25 cm), and the volatile products were distilled over as the reaction proceeded. 15 ml. of distillate were collected and rejected. The flask was cooled, and 15 ml. of water were added to the distillation residue. The distillation was then continued at a bath temperature of 150°-180°C. After 15 ml. of distillate consisting of the reaction product and water had been collected, the flask was again cooled, and the addition of water followed by distillation were repeated several times until the reaction product was completely distilled. The combined distillates were extracted with ether, after washing the extract with aqueous sodium carbonate and water and evaporation of the solvet, the residue was distilled. There were obtained 3.9 g. of pure 5-methyl-heptan-2,3-dione distilling at 45°-47°C./8 Torr. n_(D) ²³.5 = 1.4200; d₄ ²³.5 = 0.9099.

1g. 5-Methyl-octan-2,3-dione was prepared according to the same method as 5-methyl-heptan-2,3-dione, except that 0.5 mole of acetol, 0.55 mole of α-methyl-pentenal and 4.5 ml. of conc. HCl were used for the reaction. There were obtained 16 g. of pure 5-methyl-octan-2,3-dione distilling at 65°-66°C./11 Torr; n_(D) ²².5 = 1.4258; d₄ ²².5 = 0.9107.

1h. Acetylvalerianyl was prepared according to the same method as compound (1f.) It has a b.p. of 71°-72°C./44 mm. Hg.

1i. Acetylheptanoyl was prepared by hydrolyzing 3-oximo-nonan-2-one according to the method of Bouveault et al. described in Bull. Soc. Chim. France [3] 31, 1145 (1904). 3-Oximo-nonan-2-one was obtained by nitrosation of nonan-2-one with ethyl nitrite according to the method described in Org. React. VII, Chap. 6(1953). Acetylheptanoyl has a b.p. of 74°C./9 mm. Hg.

2c. 5-Methyl-heptan-3,4-dione was prepared according to the method described in Bull [3], 31, 1145 (1904). It has a b.p. of 55°C./12 mm. Hg.

the organoleptic evaluations are set out in TABLE XXIV below.

XXV -- THIOPHENE ALPHA-DIKETONES

Compounds of this group have the following general formula: ##SPC39##

wherein R₁ is hydrogen or a methyl group and wherein R₂ is an alkyl group.

Representative compounds include:1a. 1-(thienyl-2)-propane-1,2-dione n.c.b. 1-(3-methyl-thienyl-2)-propane-1,2-dione n.c.c. 1-(5-methyl-thienyl-2)-propane-1,2-dione n.c.d. 1-(thienyl-2)butan-1,2-dione n.c.

The new compounds included in this group can be obtained as follows:

1a. 1-(Thienyl-2)-propane-1,2-dione was prepared by acylating thiophene according to the method described in J.A.C.S. 72, 3695 (1950), subjecting the resulting 2-propionyl-thiophene to the action of nitrosyl chloride and hydrolyzing the reaction product in formic acid solution with nitrosyl sulfuric acid as described in Bull. [3] 31, 1163 (1904). The product formed bright yellow crystals and melted at 48°-50°C.

1b. 1-(3-methyl-thienyl-2)-propane-1,2-dione was prepared by acylating thiophene according to the method described in J.A.C.S. 72, 3695 (1950), subjecting the resulting 3-methyl-2-propionyl-thiophene to the action of nitrosyl chloride and hydrolizing the reaction product in formic acid solution with nitrosyl sulfuric acid as described in Bull. [3] 31, 1163 (1904). The product had a b.p. of 93°C./11 mm. Hg.

1c. 1-(5-Methyl-thienyl-2)-propane-1,2-dione was prepared by the same method as compound (1a.) It has a b.p. of 150°-160°C. (bath temp.)/11 mm. Hg.

1d. 1-(Thienyl-2)-butan-1,2-dione was prepared from 2-butyryl-thiophene via the oxime according to the method used in the furan series and described in Tetrahedron 20, 2959 (1964). The product has a b.p. of 120°-123°C. (bath temperature) 11 mm. Hg.

The organoleptic evaluations gave the results set out in TABLE XXV below.

XXVI -- PYRROLE ALPHA-DIKETONES

This group of compounds has the general formula: ##SPC40##

wherein R₁ is hydrogen or alkyl and R₂ is alkyl.

Representative compounds of this group include e.g.:

    1a.  (pyrrolyl-2)-propan-1,2-dione                                                                            n.c.                                            b.   (pyrrolyl-2)-butan-1,2-dione                                                                             n.c.                                       

The new compounds included in this group can be obtained as follows:

1a. (Pyrrolyl-2)-propan-1,2-dione was prepared according to the same method as used for compound (1d.) of Group XXV. It has a m.p. of 50°-51°C.

1b. (Pyrrolyl-2)-butan-1,2-dione was prepared by the same method as used for compound (1d.) of Group XXV. It has a m.p. of 37°-38°C.

Organoleptic evaluation data are set out in TABLE XXVI below.

XXVII -- FURAN ESTERS

Compounds of this group have the general formulae: ##SPC41##

wherein R is an alkyl group comprising at least 2 carbon atoms; and ##SPC42##

wherein R is an alkyl or alkenyl group.

Representative compounds of this group include:

    1a.                                                                               furfuryl propionate                                                                             *"The Furans", page 226                                    b. furfuryl butyrate                                                                               *"The Furans", page 226                                    c. furfuryl isobutyrate                                                                            *"The Furans", page 226                                    d. furfuryl isovalerate                                                                            n.c.                                                       e. furfuryl crotonate                                                                              n.c.                                                       f. furfuryl tiglate *"The Furans", page 36                                     g. furfuryl alphamethylbutyrate                                                                    n.c.                                                       h. furfuryl β,β'-dimethylacrylate                                                        n.c.                                                       i. furfuryl valerate                                                                               n.c.                                                       2a.                                                                               ethyl furnate    *"The Furans", page 513                                    b. propyl furoate   "The Furans", page 513                                     c. isopropyl furoate                                                                               *"The Furans", page 513                                    d. butyl furoate    "The Furans", page 513                                     e. isobutyl furoate *"The Furans", page 513                                    f. isoamyl furoate  "The Furans", page 513                                     g. methyl 3-(α-furyl)-propionate                                                             C.A. 32, 53977 (1938)                                      h. ethyl 3-(α-furyl)-propionate                                                              c.a.                                                        *"The Furans", Reinhold Publishing Company, New York (1953).             

The new compounds included in this group can be obtained by reacting the corresponding acid chlorides with furfuryl alcohol, e.g. according to the method described in Houben-Weyl. 4th. ed., Vol. 8, 543 (1952). There are thus obtained:

1d. Furfuryl isovalerate, b.p. 97°-98°C./11 mm. Hg.

1e. Furfuryl crotonate, b.p. 96°-98°C./11 mm. Hg.

1g. Furfuryl α-methylbutyrate, b.p. 96°C./11 mm. Hg.

1h. Furfuryl β,β'-dimethylacrylate, b.p. 113°-115°C./11 mm. Hg.

1i. Furfuryl valerate, b.p. 100°-104°C./11 mm. Hg.

In the organoleptic evaluation tests these compounds gave the results set out in TABLE XXVII below.

XXVIII -- THIOPHENE ESTERS

Compounds of this group have the following general formulae: ##SPC43##

wherein R is alkyl or furfuryl; and ##SPC44##

wherein R is hydrogen or alkyl.

Representative compounds of this group include:1a. methyl thiophene-2-carboxylate J.A.C.S. 77, 6709 (1955)b. ethyl thiophene-2-carboxylate J.A.C.S. 77, 6709 (1955)c. propyl thiophene-2-carboxylate J.A.C.S. 77, 6709 (1955)d. butyl thiophene-2-carboxylate J.A.C.S. 77, 6709 (1955)e. isoamyl thiophene-2-carboxy- n.c. latef. furfuryl thiophene-2-carboxy- n.c. late2a. thenyl formate n.c.b. thenyl acetate n.c.

The new compounds included in sub-class (1) of this group can be obtained by reacting thionyl chloride with the corresponding alkoxides according to the method described in J.A.C.S. 77, 6709 (1955). There were thus obtained:

1e. Isoamyl thiophene-2-carboxylate, b.p. 79°-80°C./0.3 mm. Hg.

1f. Furfuryl thiophene-2-carboxylate, b.p. 109°C./0.07 mm. Hg.

The new compounds included in sub-class (2) of this group can be obtained by acylation of 2-thenyl alcohol which is prepared by reducing thiophene-2-aldehyde according to the method described in J.Org.Chem. 15, 790 (1950). Acylation with the mixed anhydride of formic and acetic acids according to the method described in J.A.C.S. 64, 1583 (1942) yields

2a. Thenyl formate, b.p. 87°-88°C./15 mm. Hg.

Acylation with acetic anhydride yields

2b. Thenyl acetate, b.p. 91°C./12 mm. Hg.

In the organoleptic evaluation test these compounds gave the results set out in TABLE XXVIII below.

XXIX -- PYRIDINE ESTERS

Compounds of this group are of the general formula ##SPC45##

wherein R stands for lower alkyl and n is 0 or 1.

Representative compounds of this group include:

    1a.  methyl (pyridyl-2)-acetate                                                                               c.a.                                            b.   methyl (pyridyl-3)-acetate                                                                               c.a.                                            c.   methyl (pyridyl-4)-acetate                                                                               c.a.                                            d.   ethyl (pyridyl-2)-acetate c.a.                                            e.   ethyl (pyridyl-3)-acetate c.a.                                            f.   ethyl (pyridyl-4)-acetate c.a.                                       

Organoleptic evaluation data are set out in TABLE XXIX below.

XXX -- AROMATIC SULFUR COMPOUNDS

Compounds of this group are of the general formulae: ##SPC46##

wherein R₁ stands for hydrogen, hydroxy, alkoxy or alkyl and R₂ represents hydrogen or alkyl; ##SPC47##

wherein R₁ stands for hydrogen, hydroxy, alkyl or alkoxy, R₂ may be hydrogen or alkyl, R₃ represents alkyl or benzyl and n is 0, 1 or 2; and ##SPC48##

wherein R stands for alkyl or phenyl.

Representative compounds include:

    1a.  2-methoxy benzenethiol                                                                          Ber. 39, 1348 (1906)                                     b.   benzenethiol     c.a.                                                     c.   2-hydroxy-thiophenol                                                                            Beilstein 6, 793                                         d.   2-methyl-benzenethiol                                                                           c.a.                                                     e.   3-methyl-benzenethiol                                                                           c.a.                                                     f.   4-methyl-benzenethiol                                                                           c.a.                                                     g.   2,4-dimethyl-benzenethiol                                                                       Ber. 32, 1147                                            h.   3,4-dimethyl-benzenethiol                                                                       J.Org.Chem.26, 4047 (1961)                               i.   2-ethyl-benzenethiol                                                                            Ber. 59, 349                                             j.   2-ethoxy-benzenethiol                                                                           J.pr.Ch. 114, 231, 235                                   k.   4-methoxy-benzenethiol                                                                          c.a.                                                     2a.  methyl phenyl sulfide                                                                           c.a.                                                     b.   dibenzyl sulfide J.Chem.Soc. 1922, 1404                                   3a.  phenyl methyl disulfide                                                                         J.A.C.S. 85, 1618 (1963)                                 b.   diphenyl disulfide                                                                              Ber. 56, 1929 (1923)                                

Evaluation test data are set out in TABLE XXX below.

XXXI -- FURAN SULFUR COMPOUNDS

Compounds of this group are included in the formulae: ##SPC49##

wherein R may be hydrogen, alkyl or alkenyl and n stands for 1 or 2; ##SPC50##

wherein R₁ stands for hydrogen or alkyl, R₂ represents hydrogen, alkyl, furfuryl or alkyl-substituted phenyl, and n stands for 0, 1 or 2, with the provision that, if R₁ is hydrogen and n is 1, R₂ is neither methyl nor furfuryl; ##SPC51##

wherein R is alkyl or furfuryl; ##SPC52##

wherein R₁ represents hydrogen or alkyl and R₂ stands for alkyl or furfuryl; and ##SPC53##

wherein R represents an alkyl or an acyl group.

Representative compounds in this group include:

    1a.                                                                               furfurylthiol acetate                                                                              n.c.                                                    b. furfurylthiol propionate                                                                           n.c.                                                    c. furfurylthiol butyrate                                                                             n.c.                                                    d. furfurylthiol furoate                                                                              n.c.                                                    e. furfurylthiol β,β-dimethylacrylate                                                       n.c.                                                    f. furfurylthiol tiglate                                                                              n.c.                                                    g. furfurylthiol formate                                                                              n.c.                                                    h. 2-(furyl-2)-ethanthiol acetate                                                                     n.c.                                                    2a.                                                                               5-methylfurfuryl methyl sulfide                                                                    n.c.                                                    b. furfuryl propyl sulfide                                                                            n.c.                                                    c. furfuryl isopropyl sulfide                                                                         n.c.                                                    d. furfuryl 5-methylfuryl sulfide                                                                     n.c.                                                    e. 5-methylfuryl methyl sulfide                                                                       n.c.                                                    f. 2-(furyl-2)-ethanthiol                                                                             n.c.                                                    3a.                                                                               methylthiol furoate n.c.                                                    4a.                                                                               difurfuryl disulfide                                                                               J.A.C.S. 52, 2141 (1930)                                5a.                                                                               (benzofuryl-2)-methyl methyl sulfide                                                               n.c.                                                    b. (benzofuryl-2)-methylthiol acetate                                                                 n.c.                                               

The new compounds included in this group XXXI can be obtained as follows:

1a. Furfurylthiol acetate was prepared by reacting acetic chloride or anhydride with furfurylmercaptan according to the method described in Houben-Weyl, 4th ed., vol. 9, 753 (1955). The product has a b.p. of 90°-92°C./12 mm. Hg.

According to the same method, but starting from the corresponding acid chloride or anhydride, the following products were obtained:

1b. Furfurylthiol propionate, b.p. 95°-97°C./10 mm. Hg.

1c. Furfurylthiol butyrate, b.p. 105.5°-106.5° /10 mm. Hg.

1d. Furfurylthiol furoate, b.p. 110°C./0.01 mm. Hg.

1e. Furfurylthiol β,β-dimethylacrylate, b.p. 85°C./ 0.015 mm. Hg.

1f. Furfurylthiol tiglate, b.p. 84.5°-87.5°C./0.03 mm. Hg.

1g. Furfurylthiol formate was prepared according to the method used for the synthesis of furfuryl formate and described in J.A.C.S. 64, 1583 (1942). The product had a b.p. of 77°-78°C./ 8 mm. Hg.

1h. 2-(Furyl-2)-ethanthiol acetate was prepared by reacting thioacetic acid with 2-vinyl-furane under the action of UV light and in the presence of benzoyl peroxide according to the method described in J.Org.Chem. 27, 2853 (1962). The thio-ester, after isolation by distillation had a b.p. of 100°-103°C./ 0.05 mm. Hg.

2a. 5-Methylfurfuryl methyl sulfide was prepared by reacting 5-methylfurfuryl-mercaptan with dimethyl sulfate in alkaline solution according to known methods. 5-Methylfurfuryl-mercaptan was obtained from the corresponding alcohol by the method described in Org.Syn. 35, 67 (1955). The product is a colorless liquid boiling at 71°-72°C./11 mm. Hg.

2b. Furfuryl propyl sulfide was prepared by reacting sodium furfurylmercaptide with n-propyl bromide according to the method described in Houben-Weyl, 4th ed., vol. 9, 97 (1955). The product has a b.p. of 91°C./15 mm. Hg.

2c. Furfuryl isopropyl sulfide was prepared by the same method as used for compound (2) b., except that isopropyl bromide was used instead of n-propyl bromide. The product has a b.p. of 84°C./16 mm. Hg.

2d. Furfuryl 5-methylfuryl sulfide was prepared according to the method used for the synthesis of alkylthio-furans and described in C.A. 59, 8681d (1963). 2-Methylfuran was reacted with butyl-lithium and then with sulfur. The resulting thiol was further reacted (without prior isolation) with furfuryl chloride. The product was a slightly yellowish oil having a b.p. of 67°C./0.04-0.05 mm. Hg.

2e. Methyl 5-methylfuryl sulfide was prepared by the same method as used for compound (2) d. The product was a light yellow liquid having a b.p. of 80°C./45-50 mm. Hg.

2f. 2-(Furyl-2)-ethanethiol was prepared by saponifying 24 g. of 2-furylethanethiol acetate with alkali in aqueous-alcoholic medium. After refluxing for 90 minutes the reaction mixture was neutralized with acetic acid and then extracted with ether. Upon distillation there were obtained 14.4 g. of 2-(furyl-2)-ethanethiol having a b.p. of 61°-62°C./ 0.03 mm. Hg; n_(D) ²².3 = 1.5653; d₄ ²³.2 = 1.153

3a. Methylthiol fuorate was prepared by reacting furoyl chloride with methylmercaptan according to the method described in Houben-Weyl, 4th ed., vol. 9, 753 (1955). It has a b.p. of 92°-93°C./11 mm. Hg.

5a. Benzofurfuryl-2 methyl sulfide was prepared by reacting (benzofurfuryl-2)-mercaptan with dimethyl sulfate in alkaline solution. The sulfide thus obtained has a b.p. of 108°-109°C./0.4 mm. Hg.

The starting (benzofurfuryl-2)-mercaptan was obtained from the corresponding alcohol according to the method described in Org. Synth. 35, 67 (1955).

5b. (Benzofurfuryl-2)-thiol acetate was prepared by the same method as used for compound (1a) (furfurylthiol acetate). The product has a b.p. of 120°-122°C./0.8 mm. Hg.

Evaluation test data are set out in TABLE XXXI below.

XXXII -- THIOPHENE SULFUR COMPOUNDS

This group comprises compounds corresponding to the following general formulae: ##SPC54##

wherein R represents hydrogen, alkyl, acetyl or thenyl, and n is 1 or 2; and ##SPC55##

wherein R stands for alkyl or furfuryl.

Specific examples of compounds corresponding to these formulae include:1a. thenyl-mercaptan Compt.rend. 229, 1343 (1949)b. thenyl methyl sulfide Compt.rend. 229, 1343 (1949)c. thenylthiol acetate n.c.d. 2-(thienyl-2)-ethanethiol n.c.e. 2-(thienyl-2)-ethanethiol acetate n.c.f. dithenyl sulfide n.c.2a. thiothenoic acid 3-methyl ester n.c.b. thiothenoic acid 3-ethyl ester n.c.c. thiothenoic acid 3-furfuryl ester n.c.

The new compounds of this group can be obtained as follows:

1c. Thenylthiol acetate was prepared by the same method as used for compound (1a) (furfurylthiol acetate) of Group XXXI above. The product is a colorless liquid having a b.p. of 113°-114°C.

1d. 2-(Thienyl-2)-ethanethiol. 2-Vinyl-thiophene [obtained by the method described in Org. Synth. 38, 86 (1958)] was reacted with thioacetic acid according to the method described in J.Org.Chem. 27, 2853 (1962), and the resulting addition product was subjected to hydrolysis with an acid. The product has a b.p. of 55°C./0.1 mm. Hg.

1e. 2-(Thienyl-2)-ethanethiol acetate was obtained as the intermediate product by reacting 2-vinyl-thiophene with thioacetic acid in the preparation of compound (1d) above. The product has a b.p. of 90°C./0.07 mm. Hg.

1f. Dithenyl sulfide was prepared by the same method as used for compound (1b) (dithenyl ether) of Group X above, except that thenylmercaptan was used instead of thenyl alcohol. The product has a b.p. of 118°C./0.04 mm. Hg.

Compounds (2a), (2b) and (2c) were prepared by reacting thionyl chloride with the sodium salts of the corresponding mercaptans in alcoholic solution according to the method described in J.C.A.S. 77, 6709 (1955). After refluxing for 1 hour the reaction mixture was filtered and concentrated. The residue was purified by chromatography on a silica-gel column using a benzene-hexane mixture 8:2 as the eluant. The structure of the resulting products was identified by mass spectrometry:

2a. Thiothenoic acid S-methyl ester: Ion peaks with relative intensities: 111 (100%), 39 (22%) and 158 (12%).

2b. Thiothenoic acid S-ethyl ester: Ion peaks with relative intensities: 111 (100%), 39 (17%) and 172 (10%).

2c. Thiothenoic acid S-furfuryl ester: Ion peaks with relative intensities: 111 (100%), 81 (73.5%) and 39 (20%).

Organoleptic evaluation data are set out in TABLE XXXII below.

XXXIII -- PYRIDINE SULFUR COMPOUNDS

The compounds included in this group have the general formula: ##SPC56##

wherein R stands for hydrogen, alkyl, acyl or pyridyl, and n is 0 or 1.

As examples there can be mentioned:1a. (pyridyl-2)-methanthiol C.A. 55, 4542b (1961)b. 2-mercapto-pyridine c.a.c. 2-methylthio-pyridine n.c.d. 2-ethylthio-pyridine n.c.e. (pyridyl-2)-thiol acetate n.c.f. di(pyridyl-2)-sulfide J.Chem.Soc. 1942, 239g. 2-(pyridyl-2)-ethanethiol J.Org.Chem. 26, 82 (1961)h. 2-(pyridyl-2)-ethyl methyl sulfide see belowi. 2-(pyridyl-2)-ethyl ethyl sulfide n.c.j. 2-(pyridyl-2)-ethanethiol acetate see belowk. 2-(pyridyl-2)-ethyl furfuryl sulfide n.c.l. (pyridyl-2)-methyl methyl sulfide Helv. 47, 1754 (1964)m. (pyridyl-2)-methyl ethyl sulfide n.c.n. (pyridyl-2)-methanethiol acetate n.c.

The method used for preparing the known compound (1h) [2-(pyridyl-2)-ethyl methyl sulfide] was as follows: 2-Vinylpyridine was reacted with methylmercaptan by the action of UV light in the presence of trace amounts of benzoyl peroxide and diphenyl sulfide. The product has a b.p. of 48°C./0.03 mm. Hg.

The same method was used for preparing the known compound (1j), except that thioacetic acid was used instead of methylmercaptan. The product has a b.p. of 80°C./0.02 mm. Hg.

The new compounds included in this Group XXXIII can be obtained as follows:

1c. 2-Methylthio-pyridine was prepared according to the method described in Houben-Weyl, 4th ed., vol. 9, 7 (1955) by alkylating 2-mercapto-pyridine with methyl halide. The resulting pyridinium salt was neutralized with NaOH and the base thus obtained extracted and distilled. The product had a b.p. of 67°-68°C./10 mm. Hg.

1d. 2-Ethylthio-pyridine was prepared by the same method as used for compound (1c), except that the ethyl halide was used instead of methyl halide. The product had a b.p. of 77°-77.5°C./ 8 mm. Hg.

1e. (Pyridyl-2)-thiol acetate was prepared by reacting acetic anhydride with 2-mercaptopyridine in alkaline medium according to the method described in Houben-Weyl, 4th ed., vol. 9, 753 (1955) and in J.A.C.S. 59, 1089 (1937). The product has a b.p. of 117°-118°C./9 mm. Hg.

1i. 2-(Pyridyl-2)-ethyl ethyl sulfide was prepared by the same method as used for compound (1h), except that ethylmercaptan was used instead of methylmercaptan. The product has a b.p. of 62°C./0.005 mm. Hg.

1m. (Pyridyl-2)-methyl ethyl sulfide was prepared by the same method as used for compound 1l. The product has a b.p. of 107°-110°C./10 mm. Hg.

1n. (Pyridyl-2)-methanethiol acetate was prepared by reacting acetyl chloride with 2-mercaptomethylpyridine in alkaline medium. The product has a b.p. of 102°-103°C./9 mm. Hg.

Evaluation test data are reported in TABLE XXXIII below.

XXXIV -- PYRROLE SULFUR COMPOUNDS

These sulfur compounds correspond to the following general formula: ##SPC57##

wherein R represents alkyl, furfuryl or acyl.

As examples, there can be mentioned:1a. N-methyl-pyrryl-2 methyl sulfide n.c.b. N-methyl-pyrryl-2 ethyl sulfide n.c.c. N-methyl-pyrryl-2 furfuryl sulfide n.c.d. (N-methyl-pyrryl-2)-methylthiol acetate n.c.

The new compounds included in this Group XXXIV can be obtained as follows:

1a. N-Methyl-pyrryl-2 methyl sulfide was prepared by alkylating of N-methyl-(pyrryl-2)-methylmercaptan with methyl iodide according to the method described in Houben-Weyl, 4th ed., vol. 9, 97 (1955). The product has a b.p. of 90°C./10 mm. Hg.

1b. N-Methyl-pyrryl-2 ethyl sulfide was prepared by the same method as used for compound (1a), except that ethyl bromide was used in place of methyl iodide. The product has a b.p. of 99°C./10 mm. Hg.

1c. -N-Methyl-pyrryl-2-furfuryl sulfide was prepared by the same method as used for compound (1a), except that furfuryl chloride was used in place of methyl iodide. The product has a b.p. of 94°C./0.01 mm. Hg.

1d. (N-Methyl-pyrryl-2)-methylthiol acetate was prepared by acylating (N-methyl-pyrryl-2)-methylmercaptan according to the method described in Houben-Weyl, 4th ed., vol. 9, 753 (1958). The product has a b.p. of 69°C./0.05 mm. Hg.

Evaluation test data are set out in Table XXXIV below.

XXXV -- PYRAZINE SULFUR COMPOUNDS

The compounds of this group can be represented by the following general formulae: ##SPC58##

wherein n is 0, 1 or 2, R₁ represents hydrogen, alkyl, acyl or furfuryl and R₂ stands for hydrogen or methyl with the proviso that R₁ and R₂ cannot both be methyl if n is 0; ##SPC59##

wherein R stands for hydrogen, alkyl, furfuryl or acyl.

Illustrative examples of compounds corresponding to formulae (1) and (2) include:

    1a.                                                                               (2-methylpyrazinyl-3, -5 and-6) furfuryl sulfide                                                          n.c.                                             b. pyrazinylmethyl-mercaptan  n.c.                                             c. pyrazinylmethyl methyl sulfide                                                                            n.c.                                             d. pyrazinemethyl ethyl sulfide                                                                              n.c.                                             e. pyrazinylmethyl furfuryl sulfide                                                                          n.c.                                             f. pyrazinylmethylthiol acetate                                                                              n.c.                                             g. 2-pyrazinyl-ethyl mercaptan                                                                               n.c.                                             h. 2-pyrazinyl-ethyl methyl sulfide                                                                          n.c.                                             i. 2-pyrazinyl-ethyl ethyl sulfide                                                                           n.c.                                             j. 2-pyrazinyl-ethyl furfuryl sulfide                                                                        n.c.                                             k. 2-pyrazinyl-ethylthiol acetate                                                                            n.c.                                             2a.                                                                               2,5-dimethyl-3-mercapto-pyrazine                                                                          n.c.                                             b. 2,5-dimethyl-3-methylthio-pyrazine                                                                        n.c.                                             c. 2,5-dimethyl-3-ethylthio-pyrazine                                                                         n.c.                                             e. 2,5-Dimethyl-3-acetylthio-pyrazine                                                                        n.c.                                             d. 2,5-dimethyl-3-furfurylthio-pyrazine                                                                      n.c.                                        

The new compounds included in this group can be obtained as follows:

1a. (2-Methylpyrazinyl-3, -5 and -6) furfuryl sulfide (mixture): A mixture of 2-methyl-3-, 5- and 6-chloropyrazine was prepared by chlorination of 2-methylpyrazine according to the method described in J.Org.Chem. 26, 2356, 2360 (1961). 0.2 Mole of the above 2-methyl-chloropyrazine mixture was added to 0.2 mole of a sodium furfurylmercaptide suspension in 250 ml. of xylene. The mixture was boiled for 6 hours. After cooling 250 ml. of water were added, the organic layer was concentrated and distilled. 13.5 g. of a mixture of (2-methylpyrazinyl-3, -5 and-6) furfuryl sulfide were obtained; b.p. 153°-156°C./10 Torr; n_(D) ²⁰ = 1.5970; d₄ ²⁰ = 1.2164.

1b. Pyrazinylmethylmercaptan: a solution of 6.3 g. (0.05 mole) of chloromethylpyrazine [obtained according to the method described in J.Org.Chem. 26, 2356 (1961)] in 20 ml. of ether was added slowly, with stirring, to a solution of sodium hydrogensulfide (60%) in 50 ml. of absolute methanol. Stirring of the reaction mixture at room temperature was continued for 3 hours. The precipitate which had formed was removed by filtering, the solvents were evaporated, and the residue was dissolved in water. The solution was extracted twice with ether. The aqueous phase was neutralized with acetic acid and extracted with ether. After drying of the extract the solvent was evaporated and the residue distilled. 0.25 g. of pyrazinylmethylmercaptan boiling at 44°-45°C./0.07 mm. Hg. was obtained.

1c. Pyrazinylmethyl methyl sulfide was prepared according to the method described in Houben-Weyl, 4th ed., vol. 9, 97 (1955) by reacting chloromethylpyrazine [obtained by the method described in J.Org.Chem. 26, 2356 (1961)] with sodium methylmercaptide. The product has a b.p. of 105°-106°C./12 mm. Hg.

1d. Pyrazinylmethyl ethyl sulfide was prepared by the same method as used for compound (1c), except that sodium ethylmercaptide was used in place of sodium methylmercaptide. The product has a b.p. of 114°-116°C./12 mm. Hg.

1e. Pyrazinylmethyl furfuryl sulfide was prepared by the same method as used for compound (1c), except that sodium furfurylmercaptide was used instead of sodium methylmercaptide. The product has a b.p. of 116°C./0.05 mm. Hg.

1f. Pyrazinylmethylthiol acetate was prepared by acetylation of pyrazinylmethylthiol according to the method described in Houben-Weyl, 4th. ed., vol. 9, 735 (1955). The product has a b.p. of 52°C./0.02 mm. Hg.

1g. 2-Pyrazinyl-ethyl mercaptan was prepared by reacting vinylpyrazine [obtained by the method described in J.Org.Chem. 27, 1363 (1962)] and hydrolizing the resulting thiolic acid ester according to the method described in J.Org.Chem. 22, 980 (1957). The product has a b.p. of 56.5°-60°C./0.03 mm. Hg.

1h. 2-Pyrazinyl-ethyl methyl sulfide was prepared by reacting vinylpyrazine [c.f. J.Org.Chem. 27, 1363 (1962)] with methylmercaptan by the action of ultra violet light and in the presence of benzoyl peroxide by the method described in Acta Chem. Scand. 8, 295 (1954). The product was identified by mass spectrometry. It has a b.p. of 57°-69°C. at 0.05 mm. Hg.

1i. 2-Pyrazinyl-ethyl ethyl sulfide was prepared by the method used for compound (1h), but using ethylmercaptan. It has a b.p. of 75°C./0.03 mm. Hg.

1j. 2-Pyrazinyl-ethyl furfuryl sulfide was prepared by the method used for compound (1h), but using furfuralmercaptan. The product has a b.p. of 116°-117°C./0.01 mm. Hg.

1k. 2-Pyrazinyl-ethylthiol acetate was prepared by reacting vinylpyrazine with thioacetic acid in the presence of benzoyl peroxide as a catalyst according to the method described in J.Org.Chem. 27, 2853 (1962). The product has a b.p. of 80°C./ 0.02 mm. Hg.

2a. 2,3-Dimethyl-3-mercapto-pyrazine: A solution of 1.3 g. (0.023 mole) of sodium hydrogensulfide and 2.5 g. (0.01 mole) of 2,5-dimethyl-3-iodo-pyrazine in 70 ml. of absolute methanol was refluxed for 3 hours. After evaporation of the alcohol the residue was dissolved in 1-n NaOH, the solution was filtered and the filtrate was neutralized with acetic acid. After isolation by the usual treatments the reaction product was sublimated. There was obtained 0.81 g. of a yellow powder having a m.p. of 182°-185°C.

2b. 2,5-Dimethyl-3-methylthio-pyrazine: 2.85 g. (0.02 mole) of 2,5-dimethyl-3-chloropyrazine and 0.06 mole of methylmercaptan were dissolved in a solution of 0.7 g. of sodium in 20 ml. of absolute ethanol. The reaction mixture was refluxed for 45 minutes. After removal of the alcohol by distillation the residue was dissolved in water and the sulfide was extracted with ether and distilled. The product (yield 75.6%) has a b.p. of 40°-50°C./11 mm. Hg.

2c. 2,5-Dimethyl-3-ethylthio-pyrazine was prepared in the same manner as compound (2b), except that 0.06 mole of ethylmercaptan was used instead of methylmercaptan. The product (yield 75%) has a b.p. of 128°C./9 mm. Hg.

2d. 2,5-Dimethyl-3-furfurylthio-pyrazine was prepared in the same manner as compound (2b), except that 0.06 mole of furfurylmercaptan was used instead of methylmercaptan. The product (yield 75%) has a b.p. of 115°-120°C./0.02 mm. Hg.

2e. 2,5-Dimethyl-3-acetylthio-pyrazine was prepared by acetylating 2,5-dimethyl-3-mercapto-pyrazine [compound (2) a.] with acetic anhydride in an alkaline medium according to the method described in Houben-Weyl, 4th ed., vol. 9, 753 (1955). The product has a m.p. of 36°-42°C.

Organoleptic evaluation test data are reported in TABLE XXXV below.

XXXVI -- PHENOLS AND PHENOL ETHERS

The compounds of this group can be represented by the following general formulae: ##SPC60##

wherein R₁ represents alkyl or acetyl and R₂ represents hydrogen or methyl, with the proviso that R₁ and R₂ together comprise at least 2 carbon atoms; ##SPC61##

wherein R represents alkyl.

Examples of compounds defined by the above formulae:

(1), (2) and (3) include:1a. 2-ethyl-phenol c.a.b. 3-ethyl-phenol c.a.c. 4-ethyl-phenol c.a.d. 4-isopropyl-phenol Compt.rend. 177, 453 (1923)e. 2,3-xylenol c.a.f. 2,4-xylenol c.a.g. 2,5-xylenol c.a.h. 2,6-xylenol c.a.i. 3,4-xylenol c.a.j. 3,5-xylenol c.a.k. 2-hydroxy-acetophenone c.a.l. 2-hydroxy-propiophenone Org.Synth.13, 90 (1933)m. 4-hydroxy-propiophenone Org.Synth.13, 90 (1933)n. 5-methyl-2-hydroxy-acetophenone Ann. 460, 83 (1927)2a. 2,3,5-trimethyl-phenol c.a.b. 2,4,6-trimethyl-phenol c.a.c. 2,4,5-trimethyl-phenol c.a.d. 3,4,5-trimethyl-phenol c.a.3a. 4-ethyl-2-methoxy-phenol c.a.b. 4-propyl-2-methoxy-phenol Helv. 8, 334 (1925)

The present group also comprises the single compound (4a) 4-vinyl-1,2-dimethoxy-benzene.

Evaluation test data are set out in TABLE XXXVI below.

XXXVII -- ALIPHATIC OXOALCOHOLS

This group comprises compounds having the general formula

    R--CO--CH.sub.2 OH                                         (1)

wherein R stands for alkyl.

Examples of compounds corresponding to this definition include:1a. 2-Oxo-propan-1-ol Ann. 596, 61 (1955)b. 2-oxo-butan-1-ol Ann. 596, 68 (1955)

Flavor evaluation data are set out in TABLE XXXVII below.

XXXVIII -- MISCELLANEOUS

This group comprises compounds of the classes represented by the following general formulae: ##SPC62##

wherein R stands for hydrogen, methyl or ethyl; ##SPC63##

wherein each of the symbols X and Y represents oxygen or sulfur;

    R.sub.1 --CH.sub.2 COCH.sub.2 S--R.sub.2                   (3)

wherein R₁ represents hydrogen or alkyl and R₂ stands for alkyl or furfuryl; and ##EQU2## wherein R₁ is alkyl and R₂ stands for alkyl or furfuryl.

Specific compounds included in the above formulae are:

    1a. thiophane-3-one   J.A.C.S. 68, 2229 (1946)                                 b.  2-methyl-thiophane-3-one                                                                         Helv. 27, 124 (1944)                                     2a. 2,6-dimethyl-gamma-pyrone                                                                        Ber. 69, 2379 (1936)                                     b.  2,6-dimethyl-thio-gamma-pyrone                                                                   Ber. 52, 1539 (1919)                                     c.  2,6-dimethyl-dithio-gamma-pyrone                                                                 Compt.rend. 238, 1717 (1954)                             3a. furfurylthioacetone                                                                              n.c.                                                     b.  1-methylthio-butan-2-one                                                                         n.c.                                                     3c. methylthioacetone J.A.C.S. 76, 164 (1954)                                  4a. dimethylmercaptal of                                                           α-methylbutanal                                                                            n.c.                                                     b.  difurfurylmercaptal of                                                         α-methylbutanal                                                                            n.c.                                                      (5) a. 5-methyl-furyl-2-nitrile J.A.C.S. 54, 2549 (1932)

The new compounds included in this group XXXVIII can be obtained as follows:

3.a. Furfurylthioacetone was prepared in the same manner as methylthioacetone (cf. compound (3)c.) according to the method described in J.A.C.S. 76, 114 (1954) by condensing 0.122 mole of chloroacetone with 0.11 mole of sodium furfurylmercaptide. After the usual separation and purification of the reaction product there were obtained by distillation 13.9 g. of pure furfurylthioacetone distilling at 115°-177°C./10 Torr. n_(D) ²².8 = 1.5250; d₄ ²³ = 1.150.

3.b. 1-Methylthio-butan-2-one was prepared in the same manner as methylthioacetone according to the method described in J.A.C.S. 76, 114 (1954) by condensing 0.122 mole of 1-chloro-butan-2-one [obtained according to the method described in Ber. 82,229 (1949)] with 0.11 mole of sodium methylmercaptide. The reaction product was separated by filtration from the NaCl formed in the reaction and concentration of the filtrate. By distillation of the residue there were obtained 8.2 g. of pure 1-methylthio-butan-2-one distilling at 52°-53°C./8 Torr. n_(D) ²² = 1.4700; d₄ ²² = 0.9970.

4a. Dimethylmercaptal of α-methylbutanal: Dry HCl was introduced into a mixture of 0.05 mole α-methylbutanal and 0.11 mole methanthiol. By cooling the temperature was maintained between 0° and 5°C. After 15 minutes 50 ml. of water were added, the mixture extracted with ether, the ether layer washed with a NaHCO₃ solution and water. By distillation of the ether concentrate 4.2 g. of dimethylmercaptal of α-methylbutanal were obtained; b.p. 75°-76°C./8 Torr; n_(D) ²⁴ = 1.5050; d₄ ²⁴ = 0.9761.

4b. Difurfurylmercaptal of α-methylbutanal:

This compound was prepared by the same method as compound (4)a., using 0.11 mole of furfurylmercaptan instead of methanthiol. 6.4 g. of difurfurylmercaptal were obtained; b.p. 130°C./0.1 Torr; n_(D) ²².8 = 1.5500; d₄ ²³ = 1.126.

Organoleptic evaluation as flavor agents gave the results set out in TABLE XXXVIII below.

ORGANOLEPTIC EVALUATIONS

As was described above, the compounds of this invention were subjected to organoleptic evaluation tests either in a syrup base (A), or one of the two soluble coffee bases (B and C). The following tables give the results of these organoleptic evaluations. In the tables, the Roman numeral refers to the number of the group from which the test compounds were selected. The column headed "Number" refers to the number of the test compound of the corresponding group. The column headed "Test" gives the Method of the Test, as described hereinbefore, and the column headed "Quantity" sets out the amount of the Test Compound used in grams per 100 liters of the base material.

    ______________________________________                                         ORGANOLEPTIC EVALUATION TABLES                                                 Number                                                                               Test   Quantity  Organoleptic Characterization                           ______________________________________                                         TABLE I                                                                        1a.   A      0.2       neroli-, bergamot- and                                                         cinnamon-like; natural note                             1b.   A      0.05      green note                                              1c.   A      0.15      green note, rose-like                                   1d.   A      1         grape- and fig-like                                     1d.   C      0.03      winey, buttery, woody, nutty                            1e.   A      5         green, metallic taste                                   TABLE II                                                                       1a.   A      0.05 to   green, musty taste                                                   0.1                                                               1b.   A      0.1       oily, aromatic                                          1c.   A      0.15      oily taste                                              1d.   A      0.15      aromatic taste                                          1e.   A      1.0       aromatic taste                                          1f.   A      0.25      mouldy, tarry taste                                     1g.   A      1.0       mouldy, aromatic taste                                  1h.   A      0.25      aromatic taste                                          1i.   A      1.0       earthy taste                                            1j.   A      2.0       sweet, anise- and honey-like taste                      1k.   A      0.5       strawberry-like                                         1l.   A      0.25      earthy taste                                            1m.   A      1         slightly fruity; dry                                    1n.   A      0.15      fatty, earthy taste                                     1o.   A      0.25 - 0.50                                                                              aromatic taste                                          1p.   A      1.0       aromatic earthy taste                                   TABLE III                                                                      1a.   A      0.5       phenolic; coffee-grounds                                1a.   B      0.5-1.0   enhancement of the roasted note                         1a.   C      0.68      grounday; cereal-like                                   2a.   A      0.05      styrene-like; aromatic                                  2b.   A      1- 3      slightly phenolic; burnt taste                          2b.   B      0.4       enhancement of the bitter note                          2c.   A      0.3       salicylate-like taste                                   2d.   A      0.25      earthy flavor note                                      2e.   A      1.0       burnt, caramel taste                                    2f.   A      0.25      phenolic; saffron-like                                  2g.   B      0.12      earthy; mushroom-like; hazelnut                         2h.   B      0.50      burnt; green-taste                                      2i.   B      0.095     earthy flavor note                                      3a.   A      1.0       aromatic taste                                          3a.   C      0.1       medicinal; camphor; rioy                                3b.   A      1.0       green-cooked taste                                      3a.   C      0.11      liquorice-like; sen-sen                                 3c.   A      2.0       green-owdery taste                                      3c.   C      0.068     bitter; wintergreen mouthfeel                           TABLE IV                                                                       1a.   B      0.75      roasted; bitter; green                                  1a.   C      1.1       nitrobenzene-like                                       1b.   B      0.85      fatty; winey                                            1c.   A      1.0       styrene-like                                            1d.   A      0.5       styrene-like                                            1e.   A      1.0       chemical-like taste                                     1f.   A      0.1       styrene-like                                            1g.   C      0.11      hydrocarbon-like                                        1h.   A      0.1       burnt; horn-like; methyl lfuroate-like                  1h.   C      0.54      solvent; latex paint-like                               1i.   A      1.0       diphenyloxide-like                                      1j.   A      1.0-2.0   onion-like                                              1k.   A      1.0       green taste                                             2a.   A      0.05      styrene-like                                            2a.   C      0.01      sulfury; nutty; buckwheat-like                          3a.   A      0.25      fruity, green                                           3a.   C      0.01      geranium,metallic; acid; sulfury                        3b.   A      1.0       fruity taste                                            3c.   A      0.5       green taste                                             3c.   C      0.068     apricot, medicinal; sulfury; sour                       3d.   A      1.0       dry fruit flavor                                        4a.   A      0.025     dry phenolic taste                                      4a.   B      0.042     modified phenolic note                                  4a.   C      0.042     iodoform; sulfury                                       4b.   A      1.0       fruity; green taste                                     5a.   B      0.006     hydrocarbon; rubbery; earthy                            5b.   B      0.12      hydrocarbon; phenolic                                   TABLE V                                                                        1a.   A      0.2       burnt taste                                             1b.   A      0.1       green, fatty taste                                      1c.   A      0.03      fatty taste                                             1c.   C      0.021     aldehyde like                                           1d.   A      0.1       green taste                                             2a.   A      2.0       fruity taste                                            2a.   C      0.016     earthy, mushroom-like                                   2b.   A      0.25      gooseberry-like                                         2b.   C      0.013     geranium; green; rubbery; sulfury                       TABLE VI                                                                       1a.   B      0.6       Astringent; hazel-nut; basic taste                      1b.   B      0.25      green; earthy; hazel-nut-like                           1c.   A      0.25      caramel-like - roasted                                                         hazelnut-like taste                                     1c.   C      0.096     buttery; green; cereal; caramel                         1d.   A      0.5       green; melon-like taste                                 1e.   A      0.5-1.0   fatty taste                                             1f.   A      0.25      green, burnt, coffee-like                               1g.   A      0.25      green, fruity, strawberry-like,                                                melon-like taste                                        1h.   A      0.3       fatty; green                                            1i.   A      0.6       coffee-like                                             1i.   B      0.5       roasted, rubbery                                        1j.   A      1.0       green                                                   1j.   B      1.0       basic; bitter; astringent                               1a.   A      0.3       rum-like;                                               1k.   B      0.15      roasted; green; earthy                                  1l.   A      1.0       green                                                   1l.   B      0.2       green; astringent; earthy                               1m.   A      2.0       green                                                   1m.   B      0.6       almond-like;                                            1n.   A      0.8       green; fatty; roasted                                   1n.   B      0.25      basic; green; hazelnut-like                             1c.   A      0.2       green                                                   1c.   B      0.13      astringent, roasted; hazelnut                           1p.   B      0.6       basic; green                                            1q.   B      0.25      bitter; earthy; roasted                                 1r.   B      0.3       bitter; caramel                                         1s.   B      0.75      bitter; basic                                           1t.   B      0.45      green; astringent                                       1u.   C      0.054     winey; buttery; acid; cereal-like;                                             sulfury; caramel; solvent-like                          TABLE VII                                                                      1a.   A      0.3       burnt, hardnut taste                                    1a.   B      0.4       enhanced the woody and coffee grounds                                          note                                                    1b.   A      0.5       green, vegetable-like                                   1b.   C      0.17      earthy, potato-like                                     1c.   A      0.5       earthy flavor                                           1c.   C      0.2       green; nitrobenzene                                     1d.   A      0.5       earthy, potato-like                                     1d.   B      0.1-0.2   enhanced the woody and coffee grounds                                          notes; adds a bitter note                               1d.   C      0.084     earthy; green; sulfury; mouthfeel                       1e.   A      0.25      anise-like, liquorice flavor                            1f.   A      1.0       hazelnut, coffee-like                                   1g.   A      0.5       anise-like                                              1h.   A      2.0       slight caramel flavor                                   1i.   A      0.1       earthy; potato; hazelnut taste                          1i.   B      0.01-0.02 enhanced the coffee grounds note                        1i.   C      0.013     earthy; green; acid                                     1j.   B      0.06      earthy; hazelnut; burnt taste                           1k.   B      0.45      sweet; green; burnt; astringent note                    1l.   A      2.0       earthy note                                             1m.   A      4.0       burnt; praline-like                                     1n.   A      1.0       green; burnt note                                       1o.   A      4.0       slight coffee taste; caramel; fruity                    1p.   A      4.0       green, burnt note                                       1q.   A      2.0       burnt; coffee-like note                                 1r.   A      0.3       fresh; hazelnut; earthy note                            1r.   C      0.07      earthy; green note                                      2a.   A      3.0       coffee-like taste                                       2b.   A      0.5       burnt almond taste                                      2b.   B      0.2-0.4   enhanced woody note                                     2c.   A      2.0       hazelnut taste                                          2d.   A      4.0       mild hazelnut taste                                     2e.   A      1.0       coffee-like taste                                       2e.   B      1.0       enhanced green and nutty notes                          2f.   A      3.0       hazelnut, slightly burnt taste                          2g.   A      2.5       caramel-like, fruity taste                              2h.   A      0.5       green floral taste                                      2i.   A      1.0       anise-like taste                                        2j.   A      0.5       hazelnut-like taste                                     3a.   A      1.0       burnt, roasted hazelnut-like taste                      3a.   C      0.27      toasted                                                 3b.   A      4.0       phenolic, burnt taste                                   3c.   A      4.0       burnt, earthy taste                                     3d.   B      2.5       astringent; fatty; earthy                               3e.   B      0.7       hazelnut-like; bitter; roasted                          3f.   B      0.6       bitter; earthy                                          3g.   B      2.5       bitter; acrid; earthy                                   3h    B      1.2       bitter; astringent                                      3i.   B      2.5       bitter; acid; woody                                     3j.   B      1.2       bitter; earthy; woody                                   3k.   B      1.2       bitter; earthy; fatty                                   3l.   B      2.0       green; roasted                                          4a.   A      2.0       roasted hazelnut-like taste                             4b.   A      1.0       burnt, hazelnut-like taste                              4b.   B      1.0       enhanced the green nutty note                           4c.   A      0.5       hazelnut-like taste                                     4d.   A      4.0       fresh hazelnut taste                                    5a.   A      1.5       caramel- and coffee-like                                5b.   A      1.5       anise-like, floral taste                                5c.   A      3.0       hazelnut; slightly acid                                 5d.   A      3.0       burnt, phenolic taste                                   5e.   A      4.0       fatty taste                                             5f.   A      3.0       maple-like taste                                        5g.   A      1.0       fatty taste, slightly reminiscent                                              of chocolate                                            5h.   A      1.0       green fatty, burnt taste                                5i.   A      5.0       fatty, hazelnut-like taste                              5j.   A      1.0       coffee-like; green; earthy                              6a.   A      2.0       coffee-like taste                                       6b.   A      0.5       green taste                                             6c.   A      1.0       hazelnut-like taste                                     6d.   A      1.0       coffee-like taste                                       TABLE VIII                                                                     1a.   A      5.0       fruity taste                                            1b.   A      5.0       fruity taste                                            1c.   A      0.5-1.0   green, fruity taste                                     1d.   A      0.5       green, fatty taste                                      1e.   A      0.1       fruity, fatty taste                                     1f.   A      0.1       fatty, orange-like taste                                1g.   A      0.1       fatty, orange-like taste                                1h.   B      0.06      earthy, green taste                                     1i.   B      0.06      green, fatty taste                                      2a.   A      0.2       flowery taste                                           2b.   B      0.9       winey, woody, green note                                2c.   B      1.25      spicy taste                                             2d.   A      0.5       fruity, aromatic taste                                  2e.   A      0.5       fruity taste                                            2f.   A      0.5       fruity taste                                            2g.   A      4.0       sweet, slightly fatty taste                             2h.   A      4.0       sweet, slightly fatty taste                             2i.   A      4.0       chocolate-like taste                                    2j.   A      4.0       chocolate-like taste                                    TABLE IX                                                                       1a.   A      1.0       strong mustard taste                                    1a.   B      1.0       nutty, coffee grounds-like                              1a.   C      0.27      sulfury, rioy, phenolic taste                           1b.   A      1.0       mustard taste                                           1b.   C      0.08      buttery, groundsy taste                                 1c.   A      0.25-0.5  honey-like                                              1c.   B      1.0       coffee-grounds note                                     1c.   C      0.04      rye bread, caraway seed-like                            1d.   A      1.0       green, water-cress like                                 1d.   C      0.68      earthy, mushroom like                                   1e.   A      1.0       salicylate; coffee-like                                 1e.   C      0.14      mushroom-like                                           TABLE X                                                                        1a.   A      1.0        mustard-like taste                                     1b.   A      1.0       fruity, woody note                                      1c.   A      1.0       woody, green, elderberry-like                           TABLE XI                                                                       1a.   A      1.0       green taste                                             1b.   A      1.0       fruity, woody taste                                     1c.   A      1.0       woody, green elderberry taste                           1d.   A      5.0       slightly woody, green taste                             TABLE XII                                                                      1a.   A      0.3       burnt, mustard-like taste                               1b.   A      0.1       leathery taste                                          1b.   B      0.006     green, basic taste                                      1c.   A      4.0       caramel-like                                            1d.   A      1.0       roasted, hazelnut-like                                  1e.   A      4.0       roasted, moldy flavor                                   1f.   B      7.0       bitter, green taste                                     1g.   B      1.9       hazelnut- coffee-like taste                             1h.   B      6.0       bitter, burnt, coffee-like                              1i.   A      5.0       paper-like taste                                        1i.   B      5.0       green, roasted taste                                    1j.   B      0.3       bitter, astringent, basic taste                         TABLE XIII                                                                     1a.   B      15.0      sweet, slightly basic taste                             1b.   B      0.40      astringent, bitter, roasted note                        1c.   B      0.75      bitter, fruity, anise-like taste                        TABLE XIV                                                                      1a.   A      1.0       tonka-bean like taste                                   1a.   C      0.8       nutty, bitter almond taste                              1b.   B      0.4       bitter amond, flowery note                              1b.   C      0.08      nutty, bitter almond taste                              1c.   B      0.25      bitter, earthy taste                                    TABLE XV                                                                       1a.   A      1.0       benzaldehyde taste                                      1b.   A      1.0       cherry-like taste                                       1b.   C      0.27      bitter almond, cherry-like                              1c.   A      1.0       saffron taste                                           1c.   C      0.14      camphor note                                            1d.   A      1.0       caramel taste                                           1e.   A      1.0       burnt caramel taste                                     2a.   B      0.06      almond, caramel, buttery taste                          2b.   B      0.4       earthy, roasted, sweet aromatic taste                   2a.   C      0.07      nutty, starchy taste                                    TABLE XVI                                                                      1a.   A      2.0       burnt taste                                             1a.   B      1.0       burnt, roasted flavor                                   1b.   A      1.0       mint taste                                              1c.   C      0.16      bready taste                                            1d.   A      1.0       honey-like taste with anise note                        1e.   A      0.5       fatty, green, caraway-like taste                        1f.   A      1.0       slight mint taste                                       1g.   A      3.0       earthy taste                                            1h.   A      4.0       slightly burnt taste, slightly acid                     1i.   B      1.2       astringent, bitter taste                                1i.   C      1.35      cereal-like, metallic taste                             1j.   A      3.0       earthy taste                                            1j.   C      0.54      caramel taste                                           1k.   A      1.0       fatty, flowery taste                                    TABLE XVII                                                                     1a.   A      5.0       bread-like taste                                        1a.   B      1.25      roasted note                                            1b.   B      0.2       hazelnut, roasted, caramel note                         1c.   A      5.0       slight hazelnut note                                    TABLE XVIII                                                                    1a.   A      0.5       fruity, caramel-like note                               1b.   A      0.5       fruity note                                             1c.   A      0.2       fruity, cheesy note                                     1d.   B      0.06      green note                                              1e.   A      0.1       fruity, fatty note                                      1f.   A      0.1       fatty note                                              1g.   A      0.1       fatty note                                              1h.   A      0.1       fruity note                                             1i.   B      0.45      mushroom, earthy note                                   1j.   A      2.0       fruity note                                             1k.   A      2.0       fruity note                                             1l.   A      2.0       acetone-like                                            1m.   A      0.1       sweet taste                                             1n.   B      0.45      fruity taste                                            1o.   A      0.05      green taste                                             1p.   B      1.5       almond-like taste                                       1q.   B      0.125     earthy, green note                                      TABLE XIX                                                                      1a.   A      7.0        slight caramel-like taste                              1b.   A      4.0       slight fruity taste                                     1c.   A      4.0       fruity taste                                            1d.   A      4.0       fruity, cheesy note                                     1e.   A      4.0       light burnt taste                                       1e.   C      0.67      nutty, starchy taste                                    1f.   A      3.0       green, hazelnut-like taste                              1g.   A      2.0       green, burnt taste                                      1g.   B      4.0       astringent note                                         1g.   C      3.46      peach pit, almond taste                                 1h.   A      6.0       slight rum-like taste                                   1i.   A      2.0       fatty, green taste                                      1i.   C      0.54      nutty, spicy                                            1j.   A      3.0       green taste                                             1k.   A      5.0       weak furanic note                                       1k.   C      0.63      fruity, banana oil flavor note                          1l.   A      5.0       weak furanic note                                       1l.   B      1.0       bitter, roasted note                                    1l.   C      1.35      acid flowery note                                       1m.   A      5.0       sweet aromatic taste                                    TABLE XX                                                                       1a.   A      1.0       onion-like taste                                        1a.   B      0.5-1.0   malty, roasted note                                     1b.   A      0.25      sweet honey-like taste                                  1b.   C      0.11      nutty, starchy taste                                    1d.   A      1.0       burnt anthranilate-like taste                           1e.   A      1.0       nonalactone-like taste                                  1f.   A      1.0       wine-like taste                                         1g.   A      1.0       sweet, flowery taste                                    1h.   A      2.0       cream, caramel-like taste                               1i.   A      2.0       green, mustard-like note                                2a.   A      4.0       sweet note                                              2b.   A      5.0       slightly roasted note                                   TABLE XXI                                                                      1a.    A     2.0       fruity, rose-like taste                                 1b.   A      0.5       green taste                                             1c.   A      3.0       green taste                                             1e.   C      0.025     geranium taste                                          2a.   B      0.60      astringent, bitter, roasted taste                       2a.   C      1.35      fermented taste                                         2b.   B      0.20      astringent, peanut, roasted taste                       3a.   B      0.60      bitter, earthy, roasted taste                           3b.   A      1.00      grape-like taste                                        3b.   B      0.06      fatty, bitter, roasted taste                            3b.   C      0.06      starchy taste                                           4a.   A      4.0       weak, sweet taste                                       4b.   A      2.0       woody taste                                             TABLE XXII                                                                     1a.   A      2.0       anthranilic, burnt flavor                               1b.   A      3.0       fruity, burnt taste                                     1c.   A      0.5       burnt nutty taste                                       1c.   C      0.034     toasted, unroasted coffee bean note                     1d.   A      3.0       green, grapefruit taste                                 TABLE XXIII                                                                    1a.   A       0.12     roasted, coffee-like                                    1a.   B       0.08     hazelnut, coffee-like                                   1b.   A       2.5      chocolate-like                                          1b.   C       1.18     sulfury, starch-like                                    1c.   A       5.0      burnt, roasted note                                     1c.   B       3.0      phenolic, basic taste                                   1d.   B       7.5      burnt, coffee-like taste                                1e.   A       4.0      caramel, fatty taste                                    1e.   B       5.5      bitter, green taste                                     1f.   B       7.5      bitter, astringent note                                 1g.   A       5.0      fruity taste                                            1h.   A       4.0      caramel, fruity taste                                   1i.   B       2.0      bitter, musty taste                                     1j.   B       2.5      green, woody, fruity note                               1k.   B      45.0      astringent, bitter, musty taste                         1l.   B       5.5      bitter, coffee-like taste                               1m.   B       3.0      earthy taste                                            TABLE XXIV                                                                     1a.   A      1.0       fruity, pear-like taste                                 1a.   B      0.125     green, chocolate cream-like taste                       1b.   A      3.0       burnt buttery rum note                                  1c.   A      3.0       strawberry-like taste                                   1d.   A      1.0       caramel-like taste                                      1d.   C      0.07      acid, fermented taste                                   1e.   A      1.0       caramel-like, cocoa taste                               1e.   C      0.34      whey, nutty taste                                       1f.   A      2.0       fruity, butter-like taste                               1g.   A      0.5       fruity (melon, pear-like) taste                         1h.   B      0.1       caramel, pineapple taste                                1i.   A      1.0       fatty, rancid note                                      2a.   A      1.0       caramel-nutty taste                                     2a.   C      0.41      fruity, pineapple note                                  2b.   A      2.0       fruity taste                                            2c.   A      2.0       fruity taste                                            2d.   A      0.5       fruity taste                                            TABLE XXV                                                                      1a.   A      1.0       praline-like taste                                      1a.   B      2.0       woody, coffee grounds note                              1b.   A      2.0       fruity taste                                            1c.   A      1.0       egg-like taste                                          1c.   B      0.2-0.4   woody note                                              1d.   B      1.9       astringent, fruity, green taste                         TABLE XXVI                                                                     1a.   B      3.0       bitter, roasted peanut taste                            1b.   B      1.0       buttery, slightly meaty taste                           TABLE XXVII                                                                    1a.   A      1.0       pear-like taste                                         1a.   C      0.67      bitter, nutty taste                                     1b.   A      2.0       gooseberry-like taste                                   1c.   A      2.0       fruity, quince-like taste                               1d.   A      2.0       fruity taste                                            1e.   A      2.0       mushroom-like taste                                     1e.   C      0.07      earthy, mushroom-like                                   1f.   A      1.0       fruity taste                                            1g.   A      1.0       fruity taste                                            1h.   A      2.0       mushroom-like taste                                     1i.   B      0.08      fruity, hydrocarbon taste                               2a.   A      3.0       burnt taste                                             2a.   C      0.21      buttery, vanilla-like taste                             2b.   A      3.0       phenolic burnt note                                     2c.   B      0.15      earthy, roasted note                                    2c.   C      0.20      caraway seed note                                       2d.   B      0.09      flowery, earthy note                                    2e.   B      0.09      green, geranium note                                    2f.   A      2.0       chocolate note                                          2g.   B      0.65      spicy, winey, roasted almond taste                      TABLE XXVIII                                                                   1a.   A      1.0       anthranilate-like taste with                                                   burnt note                                              1a.   B      0.2       aromatic note                                           1a.   C      0.135     grape note                                              1b.   A      2.0       burnt taste                                             1b.   C      0.135     fermented grape, sour, winey note                       1c.   A      1.0       burnt taste                                             1d.   A      2.0       oily, burnt taste                                       1d.   C      0.126     apricot, astringent, acid, sour note                    1e.   A      2.0       oily, burnt taste                                       1e.   C      0.17      sulfury, rubbery, toasted note                          1f.   A      2.0       earthy note                                             2a.   A      1.0       mustard-like taste                                      2a.   C      0.34      sweet, solvent-like                                     2b.   A      1.0       acetate-like taste                                      TABLE XXIX                                                                     1a.   B      4.0       astringent, bitter taste                                TABLE XXX                                                                      1a.   A      0.25      roasted barley taste                                    1a.   B      0.06      roasted coffee taste                                    1a.   C      0.68      earthy, ricy taste                                      1b.   A      0.1       burnt taste                                             1b.   B      0.01      roasted flavor note                                     1b.   C      0.08      groundsy, toasted, nutty note                           1c.   A      0.5       burned, slightly rubbery note                           1d.   A      0.05      meat broth-like                                         1e.   A      0.1       burnt taste                                             1f.   A      0.05      burnt, green, fatty taste                               1g.   A      0.5-1.0   burnt, phenolic taste                                   1h.   A      0.1       burnt taste                                             1h.   B      0.03      bitter, roasted note                                    1h.   C      0.05      bitter, astringent taste                                1i.   A      0.01      burnt, meat-like taste                                  1i.   B      0.03      bitter, astringent taste                                1i.   C      0.01      sulfury brothy taste                                    1j.   A      1.0       rubbery taste                                           1k.   B      0.08      roasted taste                                           2a.   A      1.0       styrene-like taste                                      2b.   A      0.75      bitter-roasted taste                                    3a.   A      0.05      burnt, flowery note                                     3b.   B      0.05      sulfurous, earthy note                                  3b.   C      0.13      nutty, mercaptan note                                   TABLE XXXI                                                                     1a.   A      0.03      coffee taste                                            1a.   B      0.04      coffee taste                                            1a.   C      0.02      sulfury, mercaptan taste                                1b.   A      0.25      coffee-like, alliaceous note                            1c.   A      0.25      coffee-like                                             1d.   A      1.0       garlic-like                                             1e.   A      0.25      coffee-like                                             1e.   C      0.03      sulfury, sour, caramel, nutty flavor                    1f.   A      1.0       coffee-like, mushroom                                   1g.   A      0.1       coffee-like                                             1g.   C      0.01      burnt, cereal, nutty taste                              1h.   A      0.01      burnt, onion, mushroom note                             2a.   A      0.01-0.03 mustard, onion-like                                     2a.   B      0.004     bland coffee taste                                      2a.   C      0.005     geranium-like                                           2b.   A      0.05      onion-like                                              2c.   A      0.05      onion-like                                              2c.   B      0.02      astringent                                              2c.   C      0.02      nutty, astringent, bitter note                          2d.   B      0.015     fatty, earthy taste                                     2d.   C      0.013     flowery, mercaptan taste                                2e.   B      0.002     metallic, roasted note                                  2e.   C      0.006     woody, bitter, nutty taste                              2f.   A      0.001     burnt, onion, caramel note                              3a.   A      0.2-0.5   cabbage taste                                           3a.   C      0.067     sulfury, mercaptan-like                                 4a.   A      0.3       burnt coffee, metallic note                             5a.   B      0.03      metallic, sulfurous note                                5b.   B      0.06      metallic, astringent, earthy note                       TABLE XXXII                                                                    1a.   A      0.01      coffee-like                                             1a.   C      0.007     sulfurous, mercaptan                                    1b.   A      0.01      garlic-like                                             1c.   A      0.1       coffee-like                                             1c.   B      0.01      aromatic note                                           1c.   C      0.005     geranium, mercaptan, nutty note                         1d.   A      0.001     burnt, coffee grounds, onion taste                      1e.   A      0.10      burnt, onion taste                                      2a.   A      1.0       cooked vegetable-like taste                             2b.   A      1.0       burnt, coffee-like taste                                2c.   A      1.0       coffee-like                                             TABLE XXXIII                                                                   1a.   A      5.0       fortifies the bitter taste                              1a.   C      0.093     popcorn, nutty, caramel, cereal taste                   1b.   A      0.25      enhances the burnt note                                 1c.   A      0.25      enhances the phenolic note                              1d.   A      5.0       enhances the burnt note                                 1d.   C      0.025     green, acid, cereal, bitter, sour                                              note                                                    1e.   A      0.2       enhances the roast note                                 1f.   A      6.0       weak note                                               1g.   B      0.30      roasted, astringent, earthy note                        1h.   B      0.12      mushroom, bitter, green taste                           1i.   B      0.25      astringent, fatty, green taste                          1j.   B      0.40      astringent, roasted taste                               1k.   B      0.40      astringent, green note                                  1l.   B      0.30      bitter, green, earthy note                              1m.   B      0.12      metallic note                                           1n.   B      0.40      bitter fatty note                                       TABLE XXXIV                                                                    1a.   B      0.03      metallic, burnt note                                    1b.   B      0.01      metallic, earthy, burnt note                            1c.   B      0.60      astringent, sulfurous, green note                       1d.   B      0.03      metallic, sulfurous, burnt note                         TABLE XXXV                                                                     1a.   A      0.1       roasted coffee-like taste                               1a.   B      0.1       roasted, coffee grounds note                            1b.   A      2.0       roasted meat-like taste                                 1c.   A      0.1       cabbage taste                                           1c.   B      0.01-0.02 strawy, dark flavor note                                1d.   A      0.2-0.3   cabbage, onion taste                                    1e.   A      2.0       coffee-like taste                                       1e.   C      0.135     sulfury, toasted, nutty, burnt                                                 cereal note                                             2a.   A      1.0       coffee-like taste                                       2a.   C      0.135     burnt, sulfury, rubbery note                            2b.   C      0.5       turnip-like taste                                       2c.   A      3.0       burnt taste                                             2d.   A      1.0       coffee-like taste                                       2e.   A      5.0       sulfurous liver-like note                               3a.   B      1.0       earthy, sulfurous, paper-like taste                     3a.   C      1.08      acid, sulfurous taste                                   3b.   B      0.12      bitter, peanut-like                                     3b.   C      0.135     ricy, iodoform-like                                     3c.   B      0.20      hazelnut, earthy taste                                  3c.   C      0.22      burnt cereal-like taste                                 3d.   B      1.9       earthy-like                                             3d.   C      2.96      burnt cereal, bitter, spicy                             3e.   B      1.0       leathery, flowery taste                                 TABLE XXXVI                                                                    1a.   A      3.0       phenolic taste                                          1b.   A      0.05      phenolic, burnt taste                                   1c.   A      0.01-0.05 phenolic taste                                          1c.   C      0.027     solvent-like                                            1d.   A      0.01      burnt taste                                             1d.   C      0.027     phenolic                                                1e.   A      0.01      cresolic taste                                          1f.   A      0.01      burnt taste                                             1f.   B      0.02-0.04 roasted, dark flavor                                    1g.   A      0.01      phenolic taste                                          1h.   A      0.02      sweet, burnt taste                                      1h.   B      0.04      coffee, coffee grounds note                             1i.   A      0.1-0.2   slight burnt taste                                      1j.   A      0.15      balsam taste                                            1j.   B      0.1       coffee grounds note                                     1k.   A      1.5       tangerine taste                                         1l.   A      1.0       phenolic note                                           1m.   A      1.0       phenolic note                                           1n.   A      6.0       phenolic note                                           2a.   A      1.0       burnt, coffee taste                                     2a.   B      1.0       wood flavor note                                        2b.   A      0.01      coffee grounds note                                     2c.   A      2.0       phenolic note                                           2d.   A      5.0       phenolic note                                           3a.   A      0.05-0.1  burnt taste                                             3a.   B      0.1-0.2   smoky roasted flavor                                    3b.   A      1.0       weak earthy note                                        4a.   A      0.25-0.5  smoky taste                                             4a.   B      0.4       roasted, coffee grounds note                            TABLE XXXVII                                                                   1a.   A      5.0       slightly green taste                                    1b.   A      3.0       burnt, caramel, slightly buttery                        TABLE XXXVIII                                                                  1a.   A      0.1-1.0   onion, garlic taste                                     1b.   A      0.25-0.5  green, burnt coffee taste                               1b.   B      0.4       aromatic note                                           1b.   C      0.27      sulfury note                                            2a.   A      5.0       slightly bland taste                                    2b.   A      0.25      garlic, earthy taste                                    2b.   B      0.04      roasted, natural coffee taste                           2b.   C      0.027     bitter                                                  2c.   B      0.025     mushroom, paper-like                                    2c.   C      0.405     mushroom, earthy note                                   3a.   A      1.0       burnt coffee note                                       3a.   C      0.625     mercaptan note                                          3b.   B      0.025     green, sweet, fatty note                                3b.   C      0.027     earthy mushroom note                                    3c.   A      1.0       cabbage, garlic taste                                   4a.   A      0.1-0.2   earthy, coffee grounds note                             4b.   A      0.5       coffee-like                                             4b.   C      0.42      sulfury, rubbery                                        5a.   A      1.0       caramel, coumarin-like                                  5a.   B      0.5-1.0   aromatic, fresh note                                    5a.   C      0.27      nutty, bitter almond taste                              ______________________________________                                    

As has been stated above the compounds having utility in the concept of this invention may be added to substances in varying amounts to alter or to modify the flavor of the substance by masking or blanking out undesirable flavors, by enhancing or fortifying desirable flavor or flavor notes, or by adding to the original substance an entirely new and different flavor. As will also be apparent to those skilled in the art various mixtures or blends of the flavor agents described may be used to achieve a desired flavor or flavor note. If, for example, one wishes to enhance a certain flavor note, or group of flavor notes present in a substance such as coffee, one needs only mix together certain of the described flavor agents to obtain the desired result.

Following are three examples of mixtures that have been prepared in accordance with the inventive concept.

                                      TABLE XXXIX                                  __________________________________________________________________________            Compound          Parts by weight                                       Identification Name      Ex. 1                                                                               Ex. 2                                                                               EX. 3                                       __________________________________________________________________________     VII   1a.                                                                               2-methyl-3-ethyl-pyrazine                                                                      --   40   20                                          VII   1i.                                                                               2,3-diethyl-pyrazine                                                                           --   --   0.5                                         VII   1d.                                                                               2-methyl-3-isopropyl-pyrazine                                                                  5    5    7.5                                         XVII  1b.                                                                               2-acetyl-pyrazine                                                                              --   30   10                                                   2-methyl-3-methylthio-pyrazine                                                                 2    --   2                                           XXXI  1a.                                                                               furfurylthio acetate                                                                           2    2    3                                                    furfuryl methyl sulfide                                                                        --   1    --                                          XX    1a.                                                                               2-acetyl thiophene                                                                             --   80   --                                          XXXI  2b.                                                                               furfuryl propyl sulfide                                                                        --   3    1                                           XXXVIII                                                                              2b.                                                                               2,6-dimethyl-γ-thiopyrone                                                                4    4    4                                           XXX   1a.                                                                               2-methoxybenzenethiol                                                                          --   12   6                                                    2-hydroxyphenyl methyl sulfide                                                                 1    2    1.5                                         XXXVI 1i.                                                                               3,4-xylenol     4    4    2                                           XXXVI 1k.                                                                               2-hydroxyacetophenone                                                                          --   --   5                                           XXXVI 3a.                                                                               4-ethyl-2-methoxy-phenol                                                                       --   5    2.5                                         XXXVI 1c.                                                                               4-ethyl-phenol  --   --   0.5                                                  pyridine        20   30   20                                          III   2e.                                                                               2-vinyl-benzofuran                                                                             3    3    4                                           XXXVI 4a.                                                                               4-vinyl-1,2-dimethoxy-                                                                         --   40   --                                                   benzene                                                               XXVI  1a.                                                                               furfuryl propionate                                                                            --   50   --                                                   furfural        --   100  --                                          __________________________________________________________________________

When added to a commercially available soluble powdered coffee beverage these blends of flavor agents added flavor notes which enhanced the flavor of the soluble coffee in the direction of that of roasted and ground coffee which has been brewed into a coffee beverage.

In order to demonstrate the flavor modifying or enhancing effect of the compounds of this invention a base material having the following composition was prepared:

           Compound         Parts by weight                                        ______________________________________                                         3-methyl-cyclopentane-1,2-dione                                                                           50                                                  furfuryl alcohol           50                                                  furfural                   10                                                  diacetyl                    5                                                  acetylmethylcarbinol       30                                                  benzyl alcohol             100                                                 propylene glycol          755                                                                            1000                                                 ______________________________________                                    

Compounds of Group XXXV (Pyrazine Sulfur Compounds) were added to this base in varying amounts and the resulting compound mixtures were used to enhance or modify the flavor of the following food products:

a. A solution of milk sweetened with sugar, at a dosage level of 10 grams of the flavor composition per 100 kg.

b. A prepared ice-cream, at a dosage level of 10-15 g. of flavor composition per 100 kg.

c. A white cake mix, at a level of 20 g. per 100 kg. of finished cake.

d. A milk pudding, at a dosage level of 10-15 g. per 100 kg.

e. A milk chocolate, at a dosage level of 25 g. per 100 kg.

The exact formulation of the various compound mixtures are set out in the TABLE XL below.

                                      TABLE XL                                     __________________________________________________________________________     Compound             Parts by weight                                           Identification                                                                         Name         Examples                                                  __________________________________________________________________________                          4     5     6     7     8     9                           XXXV 2a 2-pyrazinyl-ethyl-                                                                          100   --    --    --    50    50                                  mercaptan                                                              XXXV 2b 2-pyrazinyl-ethyl methyl                                                                    --    30    --    --    --    5                                   sulfide                                                                XXXV 2c 2-pyrazinyl-ethyl ethyl                                                                     --    --    125   --    --20                                      sulfide                                                                XXXV 2d 2-pyrazinyl-ethyl                                                                           --    ----  100   50    35                                        furfuryl sulfide                                                               3-methyl-cyclopentane-                                                                      50    50    50    50    50    50                                  1,2-dione                                                                      furfuryl alcohol                                                                            50    50    50    50    50    50                                  furfural     10    10    10    10    10    20                                  diacetyl     5     5     5     5     5     5                                   acetylmethyl carbinol                                                                       30    30    30    30    30    30                                  benzyl alcohol                                                                              100   100   100   100   100   100                                 propylene glycol                                                                            655   725   630   655   655   655                                              1000  1000  1000  1000  1000  1000                        __________________________________________________________________________

All of the compounds of Examples 4-9 gave a resulting flavor modification in the food products which was organoleptically characterized as adding a definite roasted coffee flavor note.

A number of the Compounds of Group VII (Pyrazine Hydrocarbons) were added to the above described base material. The resulting compound mixtures had the formulations shown in TABLE XLI below.

                                      TABLE XLI                                    __________________________________________________________________________     Compound            Parts by Weight                                            Identification Name Examples                                                   __________________________________________________________________________                         10      12  13  14  15  16  17                             VII 1n 2,3-dimethyl-pyrazine                                                                       250 --  --  --  --  --  50  --                             VII 1a 2-methyl-3-ethyl-                                                                           --  25  --  --  --  20  15  10                                    pyrazine                                                                VII 1c 2-methyl-3-propyl-                                                                          --  --  45  --  --  25  --  15                                    pyrazine                                                                VII 1d 2-methyl-3-isopro-                                                                          --  --  --  45  --  --  --  20                                    pyl-pyrazine                                                            VII 1i 2-ethyl-3-ethyl-                                                                            --  --  --  --  10  --  5   2                                     pyrazine (10% soln.)                                                           3-methyl-cyclopentane-                                                                      50  50  50  50  50  50  50  50                                    1,2-dione                                                                      furfuryl alcohol                                                                            50  50  50  50  50  50  50  50                                    furfural     10  10  10  10  10  10  10  10                                    diacetyl     5   5   5   5   5   5   5   5                                     acetylmethylcarbinol                                                                        30  30  30  30  30  30  30  30                                    benzyl alcohol                                                                              100 100 100 100 100 100 100 100                                   propylene glycol                                                                            505 730 710 710 745 710 685 708                                                1000                                                                               1000                                                                               1000                                                                               1000                                                                               1000                                                                               1000                                                                               1000                                                                               1000                           __________________________________________________________________________

When added to the same food products at the same dosage levels as described in connection with the Examples of TABLE XL above, the compound mixtures of Examples 10-17 imparted a pronounced nutty, green, fresh, earthy flavor note, with a light note of coffee grounds, to the foods.

Further compound mixtures utilizing mixtures of compounds from Group XXXV (Pyrazine Sulfur Compounds) and from Group VII (Pyrazine Hydrocarbons) were made as set out in TABLE XLII below.

                                      TABLE XLII                                   __________________________________________________________________________     Compound              Parts by weight                                          Identifiaction Name   Examples                                                 __________________________________________________________________________                           18  19  20  21                                           XXXV 2a                                                                               2-pyrazinyl-ethylmercaptan                                                                    20  20  20  20                                           XXXV 2d                                                                               2-pyrazinyl-ethyl furfuryl                                                                    20  20  20  20                                                  sulfide                                                                  VII 1a                                                                               2-methyl-3-ethyl-pyrazine                                                                     --  --  10  10                                            VII 1d                                                                               2-methyl-3-propyl-pyrazine                                                                    --  --  20  5                                             VII 1i                                                                               2,3-diethyl-pyrazine                                                                          --  10  --  5                                                   (10% solution) -                                                                              3-methyl-cyclopentane-                                                             50  50  50  50                                              1,2-dione                                                                      furfuryl alcohol                                                                              50  50  50  50                                                  furfural       10  10  10  10                                                  diacetyl       5   5   5   5                                                   acetylmethylcarbinol                                                                          30  30  30  30                                                  benzyl alcohol 100 100 100 100                                                 propylene glycol                                                                              715 705 685 695                                                                1000                                                                               1000                                                                               1000                                                                               1000                                         __________________________________________________________________________

When added to the same food products as above and in the same dosage levels, the foods were found to have their flavor modified to one with a definite coffee flavor with a light touch of a coffee grounds note.

Some further compound mixtures were prepared from compounds of Group VII (Pyrazine Hydrocarbons) using as a base the following mixture:

                          Parts by weight                                          3-methyl-cyclopentane-1,2-dione                                                                        200                                                    Essence of cinnamon     10                                                     Essence of sweet fennel 20                                                     Essence of star anise   20                                                     benzyl alcohol          250                                                    propylene glycol        500                                                                            1000                                              

The exact formulations of these compound mixtures are set out in TABLE XLIII below.

                                      TABLE XLIII                                  __________________________________________________________________________     Compound               Parts by weight                                         Identification Name    Examples                                                __________________________________________________________________________                            22  23  24  25  26                                      VII 1e 2-methyl-3-butyl-pyrazine                                                                      25  --  --  --  5                                       VII 1b 2-methyl-3-isobutyl-pyrazine                                                                   --  50  --  --  15                                      VII 1f 2-methyl-3-amyl-pyrazine                                                                       --  --  100 --  20                                      VII 1g 2-methyl-3-hexyl-pyrazine                                                                      --  --  --  50  15                                             3-methyl-cyclopentane-1,2-                                                                     200 200 200 200 200                                            dione                                                                          Essence of cinnamon                                                                            10  10  10  10  10                                             Essence of sweet fennel                                                                        20  20  20  20  20                                             Essence of star anise                                                                          20  20  20  20  20                                             benzyl alcohol  250 250 250 250 250                                            propylene glycol                                                                               475 450 400 450 445                                                            1000                                                                               1000                                                                               1000                                                                               1000                                                                               1000                                    __________________________________________________________________________

When added to a soft gum-drop candy formulation at a dosage level of 30 g. per 100 kg., to an ice-cream mix at a dosage level of 8-10 g. per 100 kg., to a milk pudding mix at a dosage level of 8-10 g. per 100 kg., and to a hard candy formulation at a dosage level of 15-20 g. per 100 kg., the compound mixtures imparted a definite anise, liquorice-like flavor note to the finished products.

It should be kept in mind, as will be appreciated by those skilled-in-the-art, that with many flavors it is possible to imitate the natural flavor by selecting a limited number of the flavor enhancing substances examplified above. Coffee aroma, on the other hand, is much more complex than the ordinary flavoring materials and may necessitate the combination of many more of the examplified ingredients for reproduction.

It will also be understood that whereas the preferred embodiment of this invention is directed toward the enhancement or modification of coffee flavors, the concept of the invention has much wider application. While some of the compounds may be characterized by terms which are not directly related to coffee flavors, these compounds, when used in more complex formulae, may contribute desirable flavor notes to the overall flavor and aroma.

To summarize briefly this invention relates to a group of chemical compounds which have been found to have utility for the alteration or modification of the flavor of other materials. These compounds, called flavor agents or flavor modifiers, may be used in minute quantities to enhance the natural flavor of substances to which they are added, or to alter or modify a flavor which is undesirable, or to impart to a substance additional or different flavors or flavor notes. The flavor agents of the invention are used in minor, but flavor altering amounts, in any case, in quantities sufficient to obtain the desired results. The flavor modifiers are of particular importance and usefulness in the modification, alteration or enhancement of the flavor of coffee beverages made from soluble coffee and the preferred embodiment of the invention contemplates their use in conjunction with such products.

The flavor agents of the invention may be added at a convenient step in the soluble coffee process such as plating the dried soluble coffee with a desired dilution of the flavor agent in an acceptable solution followed by drying. In certain instances the desired agent may be added directly to a concentrated coffee extract and the mixture dried into a soluble coffee product which contains the flavor agent as an integral part thereof. Other methods of incorporation of the agents will suggest themselves to those skilled in the art and may, of course, be used without departing from the inventive concept, which may be described as being a composition of matter comprising a combination of a soluble coffee product, however prepared, whether liquid or solid, concentrated or dilute, which contains combined therewith a minor, but flavor modifying amount, of a flavor agent as described herein. 

What is claimed is:
 1. The compound furfurylthioacetone. ##SPC64##wherein R is hydrogen or an alkyl group, e.g. methyl or ethyl, at least one of the R's being an alkyl group. Typical compounds include:

    1a.  alpha-methyl-naphthalene  c.a.                                            b.   beta-methyl-naphthalene   c.a.                                            c.   beta-ethyl-naphthalene    c.a.                                            d.   1,2-dimethyl-naphthalene  c.a.                                            e.   1,3-dimethyl-naphthalene  c.a.                                            f.   1,4-dimethyl-naphthalene  c.a.                                            g.   1,5-dimethyl-naphthalene  c.a.                                            h.   1,6-dimethyl-naphthalene  c.a.                                            i.   2,3-dimethyl-naphthalene  c.a.                                            j.   2,6-dimethyl-naphthalene  c.a.                                            k.   1,3,7-trimethyl-naphthalene                                                                              c.a.                                            l.   2,3,5-trimethyl-naphthalene                                                                              c.a.                                            m.   2,3,6-trimethyl-naphthalene                                                                              c.a.                                            n.   alpha-ethyl-naphthalene   c.a.                                            o.   1,7-dimethyl-naphthalene  c.a.                                            p.   2,7-dimethyl-naphthalene  c.a.                                        